A E Farn writes:
..........it has been mooted among people in the jewelry trade that there are two kinds of gemologists. The one, shall we say, the front-line troops who absorb the assaults of the gem-querying customer. The other, the support troops, who furnish the ammunition to them in the guise of theoretical and practical explanations. It is said that the late Harry Truman, when President of the United States of America, had on his desk a notice which indicated ‘the buck stops here.’ Likewise, we in the laboratory of the London Chamber of Commerce feel the same way about jewelry tests. Provided the item is jewelry in the broad sense—we should be able to furnish the answer. We are not magic, we are almost human, we have certain skills which predominate and between the useful combination of experience, skill, training, aptitude, comparison stones, notes, books and stored-up knowledge, we come to a decision on most items..........
Saturday, July 21, 2007
Hauyne (Hauynite)
Chemistry: Complex sodium aluminum silicate
Crystal system: Cubic; dodecahedral or octahedral (rounded grains).
Color: Transparent to translucent; blue, white, gray, green, yellow, red.
Hardness: 6
Cleavage: Distinct: 1 direction; Fracture: brittle, conchoidal to uneven.
Specific gravity: 2.4
Refractive index: 1.496; SR (isotropic)
Luster: Vitreous to greasy.
Dispersion: -
Dichroism: -
Occurrence: Igneous rocks; under saturated lavas; Italy, Germany (Rhineland).
Notes
A constituent of lapis lazuli; sulphur-rich hauyne called ‘lazurite’; translucent and the rare type blue crystals cut for collectors; faceted, cabochon.
Crystal system: Cubic; dodecahedral or octahedral (rounded grains).
Color: Transparent to translucent; blue, white, gray, green, yellow, red.
Hardness: 6
Cleavage: Distinct: 1 direction; Fracture: brittle, conchoidal to uneven.
Specific gravity: 2.4
Refractive index: 1.496; SR (isotropic)
Luster: Vitreous to greasy.
Dispersion: -
Dichroism: -
Occurrence: Igneous rocks; under saturated lavas; Italy, Germany (Rhineland).
Notes
A constituent of lapis lazuli; sulphur-rich hauyne called ‘lazurite’; translucent and the rare type blue crystals cut for collectors; faceted, cabochon.
Friday, July 20, 2007
The Formula
Memorable quote (s) from the movie:
Tom (Chris Hanel): If you would have asked me a month ago, why I was making this fanfilm, I really don't know what I would have said. For the experience, recognition, chance at fame... stupid excuse to make a lightsaber duel? Revenge would have been my most honest answer, but still not the right one. The real reason for anyone, anyone to make a fanfilm, in my opinion - Man, just have fun. My film isn't going to change the world, I understand that. But I learned a lot, and I had a lot of laughs because I made it with my friends. And if you're not having fun... why are you making this fanfilm in the first place? Who cares if your film's not perfect? Who cares what other viewers or some stupid short-sighted radio critic says on some flashy website? Sometimes you have to step back and say, "Hey, it's only a movie."
Tom (Chris Hanel): If you would have asked me a month ago, why I was making this fanfilm, I really don't know what I would have said. For the experience, recognition, chance at fame... stupid excuse to make a lightsaber duel? Revenge would have been my most honest answer, but still not the right one. The real reason for anyone, anyone to make a fanfilm, in my opinion - Man, just have fun. My film isn't going to change the world, I understand that. But I learned a lot, and I had a lot of laughs because I made it with my friends. And if you're not having fun... why are you making this fanfilm in the first place? Who cares if your film's not perfect? Who cares what other viewers or some stupid short-sighted radio critic says on some flashy website? Sometimes you have to step back and say, "Hey, it's only a movie."
The Indian Retail Industry
According to Research and Market report, the Indian retail industry may become a US$175-200 billion business by 2016. More info @ http://www.researchandmarkets.com
More Demand, More Questions
Konstantin Akinsha writes about the emerging Russian/East European art (s) + forgeries + other viewpoints @ http://artnews.com/issues/article.asp?art_id=2246
Gem and jewelry are good comparisons. Who can tell you whether the gem and jewelry you see on dispaly are real? Today experience + visual observations skills are not enough. Keeping up with fraudsters is difficult. They are always one step ahead. Most gemstones created in the laboratory, or enhanced by heat or chemical/special treatments are fine, but are not stated openly. In order to improve color, clarity + overall quality gemstones may be oiled, waxed, dyed, bleached, coated with lacquer or enamel, heat treated (with or without pressure), irradiated with neutrons, gamma rays or beta particles, surface diffused, glass/plastic filled (to add weight + toughen + hide surface/structural flaws), depending on the gemstone species. If you are doubtful always consult a reputed gem testing laboratory.
Gem and jewelry are good comparisons. Who can tell you whether the gem and jewelry you see on dispaly are real? Today experience + visual observations skills are not enough. Keeping up with fraudsters is difficult. They are always one step ahead. Most gemstones created in the laboratory, or enhanced by heat or chemical/special treatments are fine, but are not stated openly. In order to improve color, clarity + overall quality gemstones may be oiled, waxed, dyed, bleached, coated with lacquer or enamel, heat treated (with or without pressure), irradiated with neutrons, gamma rays or beta particles, surface diffused, glass/plastic filled (to add weight + toughen + hide surface/structural flaws), depending on the gemstone species. If you are doubtful always consult a reputed gem testing laboratory.
Botswana’s 15% Stake In De Beers: To Sell Or Not To Sell Is Not The Question – The Timing Is!
Chaim Even-Zohar writes about Botswana's diversification plans to compete with other players + the Nicky factor + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp?TextSearch=&KeyMatch=0&id=25942
Notes From The Laboratory
2007: Here is another tip from my mentor. Fuel for thought. This is done even today. Keep your eyes open.
(via The Journal of Gemmology, Vol.XIX, N0.2, April 1984) Kenneth Scarratt writes:
An item that we have seen quite a number of examples of over the past few years is the imitation crystal.
One interesting specimen made to imitate ruby was composed of fragments of natural and synthetic (Verneuil) ruby together by an adhesive and coated in mica. More often than not though, these imitations are made to resemble emerald, in particular the type of mica-coated rough that emanates from East Africa.
Sometimes produced with obvious crystal form, or more convincingly with the minimum of form, the basic material for this type of imitation is either very poor quality emerald, beryl or glass. The poor quality emerald or beryl varieties may be manufactured either by slicing the crystal down its length and gluing the two pieces back together with a green adhesive and then coating the whole in mica, or by hollowing out the crystal, infilling with a green substance and then coating the base with a matrix-like material.
(via The Journal of Gemmology, Vol.XIX, N0.2, April 1984) Kenneth Scarratt writes:
An item that we have seen quite a number of examples of over the past few years is the imitation crystal.
One interesting specimen made to imitate ruby was composed of fragments of natural and synthetic (Verneuil) ruby together by an adhesive and coated in mica. More often than not though, these imitations are made to resemble emerald, in particular the type of mica-coated rough that emanates from East Africa.
Sometimes produced with obvious crystal form, or more convincingly with the minimum of form, the basic material for this type of imitation is either very poor quality emerald, beryl or glass. The poor quality emerald or beryl varieties may be manufactured either by slicing the crystal down its length and gluing the two pieces back together with a green adhesive and then coating the whole in mica, or by hollowing out the crystal, infilling with a green substance and then coating the base with a matrix-like material.
Hambergite
Chemistry: Berylium borate
Crystal system: Orthorhombic; prism; flattened.
Color: Transparent to translucent; colorless, gray, yellow.
Hardness: 7.5
Cleavage: Perfect: 2 directions; Fracture: brittle, conchoidal to uneven.
Specific gravity: 2.35
Refractive index: 1.553 – 1.631; Biaxial positive; 0.072
Luster: Vitreous.
Dispersion: Low.
Dichroism: -
Occurrence: In pegmatites; Madagascar, Norway.
Notes
Collector’s stone; high DR and vitreous luster (looks like glass); rare; seldom very clean; lowest known density for gem with such a high birefringence; faceted.
Crystal system: Orthorhombic; prism; flattened.
Color: Transparent to translucent; colorless, gray, yellow.
Hardness: 7.5
Cleavage: Perfect: 2 directions; Fracture: brittle, conchoidal to uneven.
Specific gravity: 2.35
Refractive index: 1.553 – 1.631; Biaxial positive; 0.072
Luster: Vitreous.
Dispersion: Low.
Dichroism: -
Occurrence: In pegmatites; Madagascar, Norway.
Notes
Collector’s stone; high DR and vitreous luster (looks like glass); rare; seldom very clean; lowest known density for gem with such a high birefringence; faceted.
Thursday, July 19, 2007
Gemstones vs. Chocolates
The chocolate companies in the US and elsewhere have started labeling their bars according to cacao content (cocoa solids + cocoa butter). The experts believe chocolate's taste is a magic combination of origin + blend + roasting of the cocoa beans. Many industry analysts believe the next wave in chocolate marketing will be focussed on origin + variety of cocoa beans.
I think the colored stone + diamond industry have a lot to learn from the chocolate industry. If the grading laboratories were able to classify origin, variety, treatments + product contents (chemistry) in a easy-to-read (understand) format, the concept could have made a big difference.
I think the colored stone + diamond industry have a lot to learn from the chocolate industry. If the grading laboratories were able to classify origin, variety, treatments + product contents (chemistry) in a easy-to-read (understand) format, the concept could have made a big difference.
Nuclear Regulatory Commission
In the US, discussions are underway to enforce NRC (Nuclear Regulatory Commission) regulations on treated gems, especially when dealing with irradiated gems because most of the gems comes from overseas. In the US, many gemstones are sold in noncompliance with NRC regulations, and there are no NRC-licensed facilities to test gemstones. Many in gem and jewelry industry, especially jewelry retailers do not like nasty surprises during the Christmas season.
The new regulations may be ready by early next year with reference to tool kit on treated gems. For more information visit http://www.nrc.gov
The new regulations may be ready by early next year with reference to tool kit on treated gems. For more information visit http://www.nrc.gov
Operating Under Umbrellas
Chaim Even-Zohar writes about the way (s) diamond banker (s) think and make decisions + transparency and accountability + an insider view + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.aspTextSearch=&KeyMatch=0&id=25974
Gold Rush
Eileen Kinsella writes about Gustav Klimt and his paintings + the price factor (s) + other viewpoints @ http://artnews.com/issues/article.asp?art_id=2193
Like art, gemstones are an imperfect market, with a sale possible only when there is a willing buyer and all prices are open negotiation. Many were shocked when Gustav Klimt's Portrait of Adele Bloch-Bauer I (1907) was sold at $135 million, surpassing ($104.2 million) Picasso's Blue Period Boy with a Pipe (1905). The reason may be the painting's provenance + history. Beauty is in the eye of the beholder.
The story of Hancock Red Diamond is a good comparison. In the 1980s the heirs of Warren Hancock owed the IRS a million dollars. In order to pay the bill they shipped off the gem collection their dad stashed away for years to the Sotheby's in New York for evaluation. Sotheby's picked out three, the largest of the trio, a 0.95ct red diamond was bought for $880,000 + 10% buyer's premium; that set a world record of $926,000 per carat. Warren Hancock had bought all three diamonds from his local jeweler for less than $20000 combined.
On February 15, 2006, for a 8.62 carat cushion-cut ruby (Burmese) Lawrence Graff paid a price of US$425,000 per carat. Again, the reason may be the stone's provenance, beauty + a good story.
In my view, because of gemstone's beauty, rarity, durability + portability, the stones should fetch more than paintings.
Like art, gemstones are an imperfect market, with a sale possible only when there is a willing buyer and all prices are open negotiation. Many were shocked when Gustav Klimt's Portrait of Adele Bloch-Bauer I (1907) was sold at $135 million, surpassing ($104.2 million) Picasso's Blue Period Boy with a Pipe (1905). The reason may be the painting's provenance + history. Beauty is in the eye of the beholder.
The story of Hancock Red Diamond is a good comparison. In the 1980s the heirs of Warren Hancock owed the IRS a million dollars. In order to pay the bill they shipped off the gem collection their dad stashed away for years to the Sotheby's in New York for evaluation. Sotheby's picked out three, the largest of the trio, a 0.95ct red diamond was bought for $880,000 + 10% buyer's premium; that set a world record of $926,000 per carat. Warren Hancock had bought all three diamonds from his local jeweler for less than $20000 combined.
On February 15, 2006, for a 8.62 carat cushion-cut ruby (Burmese) Lawrence Graff paid a price of US$425,000 per carat. Again, the reason may be the stone's provenance, beauty + a good story.
In my view, because of gemstone's beauty, rarity, durability + portability, the stones should fetch more than paintings.
Harry Collins: The Royal Jeweler
Harry Collins, a small family-run business is the Queen of England's new royal jeweler, who will be responsible for the maintenance of the royal jewelry collection.
Fibrolite (Sillimanite)
Chemistry: Aluminum silicate
Crystal system: Orthorhombic; long slender prisms without distinct termination; often in parallel groups; also massive.
Color: Transparent to translucent; blue to blue/green, brown; phenomena: frequently fibrous giving cat’s eye.
Hardness: 6 - 7.5
Cleavage: Perfect: 1 direction, parallel to one long prism face.
Specific gravity: 3.25
Refractive index: 1.658 – 1.678; Biaxial positive; 0.02
Luster: Vitreous to silky.
Dispersion: Low.
Dichroism: Strong: pale green/dark green/blue.
Occurrence: Schists, gneisses and granites; Burma, Sri Lanka, USA.
Notes
Frequently fibrous; alternate name Sillimanite (after B Sillimand, a one-time professor at Yale University, USA); often reserved for fibrous massive variety found in Idaho, USA; polymorphous with andalusite and kyanite; fluorescence: weak red in transparent blue material; indistinct spectral bands in blue 462, 441, 410nm; faceted and cat’s eye (cabochon).
Crystal system: Orthorhombic; long slender prisms without distinct termination; often in parallel groups; also massive.
Color: Transparent to translucent; blue to blue/green, brown; phenomena: frequently fibrous giving cat’s eye.
Hardness: 6 - 7.5
Cleavage: Perfect: 1 direction, parallel to one long prism face.
Specific gravity: 3.25
Refractive index: 1.658 – 1.678; Biaxial positive; 0.02
Luster: Vitreous to silky.
Dispersion: Low.
Dichroism: Strong: pale green/dark green/blue.
Occurrence: Schists, gneisses and granites; Burma, Sri Lanka, USA.
Notes
Frequently fibrous; alternate name Sillimanite (after B Sillimand, a one-time professor at Yale University, USA); often reserved for fibrous massive variety found in Idaho, USA; polymorphous with andalusite and kyanite; fluorescence: weak red in transparent blue material; indistinct spectral bands in blue 462, 441, 410nm; faceted and cat’s eye (cabochon).
Wednesday, July 18, 2007
Is She Smiling For Two
Visual observation (s) alone won't help identify paintings and gemstones. The concept/technique (s) used for identifying origin / treatments of paintings are very similar to origin and treatments detection of gemstones with analytical instruments. The results are always surprising.
Laurie Hurwitz writes about the advanced three dimensional high resolution laser scanning system the experts used for extensive analysis of the Mona Lisa portrait + other viewpoints @ http://artnews.com/issues/article.asp?art_id=2194
Laurie Hurwitz writes about the advanced three dimensional high resolution laser scanning system the experts used for extensive analysis of the Mona Lisa portrait + other viewpoints @ http://artnews.com/issues/article.asp?art_id=2194
21 Grams
Memorable quotes from the movie:
Paul Rivers (Sean Penn): How many lives do we live? How many times do we die? They say we all lose 21 grams... at the exact moment of our death. Everyone. And how much fits into 21 grams? How much is lost? When do we lose 21 grams? How much goes with them? How much is gained? How much is gained? Twenty-one grams. The weight of a stack of five nickels. The weight of a hummingbird. A chocolate bar. How much did 21 grams weigh?
Paul Rivers (Sean Penn): How many lives do we live? How many times do we die? They say we all lose 21 grams... at the exact moment of our death. Everyone. And how much fits into 21 grams? How much is lost? When do we lose 21 grams? How much goes with them? How much is gained? How much is gained? Twenty-one grams. The weight of a stack of five nickels. The weight of a hummingbird. A chocolate bar. How much did 21 grams weigh?
JCOC.tv
On August 1, 2007, the Jewelry Consumer Opinion Council (JCOC.net) will be launching its video uploads, a cross between You Tube and The Knot : to entertain and educate consumer (s) to buy gems, jewelry and watches.
For more information contact Melina Trujillo at (800) 421-9339 ext.103, mtrujillo@mvimarketing.com or visit JCOC.tv
For more information contact Melina Trujillo at (800) 421-9339 ext.103, mtrujillo@mvimarketing.com or visit JCOC.tv
Mixed Signals From Botswana
Chaim Even-Zohar writes about Botswana government's beneficiation policy + diamond manufacturing rush in Botswana + foreign direct investment in the diamond sector + attitude (s) toward foreigners + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp?TextSearch=&KeyMatch=0&id=26043
Te Za Mines Jade With Sophisticated Equipment In Phakant
KNG writes about the famous Phakant jade mines in Burma + the key players behind the mining venture (s) @ http://www.kachinnews.com/read.aspCatId=14&NewsId=621&Title=Te+Za+mines+jade+with+sophisticated+equipment+in+Phakant
Investing In Gems For Fun And Profit
Pat Curry writes about intriguing stories that fuel the desire to invest in gems + the do's and dont's + gemstone addiction + other viewpoints @ http://www.bankrate.com/brm/news/investing/20031103a1.asp
Botswana Pins Hollywood Hopes On Detective Film
Moabi Phia writes about Botswana government's controversial move to promote a new film based on Alexander McCall's best selling fiction series 'The No.1 Ladies Detective Agency' by Anthony Minghella (Cold Mountain/The English Patient) + other viewpoints @ http://www.reuters.com/article/filmNews/idUSL0987692020070710?pageNumber=3&sp=true
Notes From The Laboratory
2007: Here is an excellent insight to identification (diamond) from my mentor.
(via The Journal of Gemmology, Vol.XIX, N0.2, April 1984) Kenneth Scarratt writes:
It is not unusual for a group of gemologists to disagree over the color of gemstone. Some colored diamonds in particular tend to possess colors which are most difficult to describe. However, when you see a diamond actually change color from one distinct color to another before your eyes it can shake any confidence you may have in your own eyesight.
Such was the case when late one afternoon I decided to make start on identifying the nature (natural or treated) of the color of 2.02 ct brilliant-cut diamond. All I really had time for was to make out my worksheet, giving a full description of the stone, and a short microscopic examination before it had to go into the safe for the night. On the worksheet I stated in a most positive fashion that the color of the stone was green. The next morning when the safe was opened I immediately retrieved the envelope containing the diamond, took it to a work bench and removed the stone from it. There before me lay a brilliant yellow stone. After checking the envelope to make sure that it was the one I put in the safe the night before (it was) I decided to check the stone’s weight against my record, but as I picked it up to take it to the balance its color started to change through various shades of yellow and yellow/green until it was back to the color it was the night before.
These so-called ‘chameleon diamonds’ have been reported upon before, and the change has been variously described as being associated with changes in temperature or in the amount of light reaching the stone. A manufacturer would notice the effect because it is said that these stones glow red on ‘the wheel’ and change to yellow shortly afterwards, from which they return to their normal green at room temperature; whereas a trader might become aware of the type of stone he had in a similar manner to that in which I had become aware of the peculiarities of this stone.
The color change from green to yellow, unless one includes the slight cooling which may occur if the stone is placed in a safe overnight, is usually described as being dependant upon a temperature increase, such as placing the stone on a hot plate, rather than a decrease; and so it was interesting to discover that when we reduced the temperature of this stone to at first 120K in the laboratory and then to 77K at King’s College, London, whilst recording the spectra, the color of this stone once again became a brilliant yellow.
The differences between the room and low temperature spectra are quite evident. The general appearance of the spectrum at room temperature is approaching that of a normal Type 1b with a weak 415 (Type 1a) peering out of the gloom and an unusual absorption hump covering the yellow, orange, red and N.I.R—the are of greatest transmission being in the green. At the lower temperatures there is clearly a sharpening up of the 415, but more importantly there is a lessening of the absorption hump in the red, orange and yellow, allowing the stone to transmit to a greater extent in this region as well as in the green, thus resulting in a yellow stone.
One assumes that changes of a similar nature may take place when the stone is heated; however, we restricted ourselves to room and low temperature spectroscopy only. The luminescence effects produced by this tone were—long wave ultraviolet, a very strong bright yellow followed by a very strong greenish phosphorescence; short wave ultraviolet, a strong and bright yellow/green followed by a very strong greenish phosphorescence; and X-rays, a blue/green followed by a strong green phosphorescence.
(via The Journal of Gemmology, Vol.XIX, N0.2, April 1984) Kenneth Scarratt writes:
It is not unusual for a group of gemologists to disagree over the color of gemstone. Some colored diamonds in particular tend to possess colors which are most difficult to describe. However, when you see a diamond actually change color from one distinct color to another before your eyes it can shake any confidence you may have in your own eyesight.
Such was the case when late one afternoon I decided to make start on identifying the nature (natural or treated) of the color of 2.02 ct brilliant-cut diamond. All I really had time for was to make out my worksheet, giving a full description of the stone, and a short microscopic examination before it had to go into the safe for the night. On the worksheet I stated in a most positive fashion that the color of the stone was green. The next morning when the safe was opened I immediately retrieved the envelope containing the diamond, took it to a work bench and removed the stone from it. There before me lay a brilliant yellow stone. After checking the envelope to make sure that it was the one I put in the safe the night before (it was) I decided to check the stone’s weight against my record, but as I picked it up to take it to the balance its color started to change through various shades of yellow and yellow/green until it was back to the color it was the night before.
These so-called ‘chameleon diamonds’ have been reported upon before, and the change has been variously described as being associated with changes in temperature or in the amount of light reaching the stone. A manufacturer would notice the effect because it is said that these stones glow red on ‘the wheel’ and change to yellow shortly afterwards, from which they return to their normal green at room temperature; whereas a trader might become aware of the type of stone he had in a similar manner to that in which I had become aware of the peculiarities of this stone.
The color change from green to yellow, unless one includes the slight cooling which may occur if the stone is placed in a safe overnight, is usually described as being dependant upon a temperature increase, such as placing the stone on a hot plate, rather than a decrease; and so it was interesting to discover that when we reduced the temperature of this stone to at first 120K in the laboratory and then to 77K at King’s College, London, whilst recording the spectra, the color of this stone once again became a brilliant yellow.
The differences between the room and low temperature spectra are quite evident. The general appearance of the spectrum at room temperature is approaching that of a normal Type 1b with a weak 415 (Type 1a) peering out of the gloom and an unusual absorption hump covering the yellow, orange, red and N.I.R—the are of greatest transmission being in the green. At the lower temperatures there is clearly a sharpening up of the 415, but more importantly there is a lessening of the absorption hump in the red, orange and yellow, allowing the stone to transmit to a greater extent in this region as well as in the green, thus resulting in a yellow stone.
One assumes that changes of a similar nature may take place when the stone is heated; however, we restricted ourselves to room and low temperature spectroscopy only. The luminescence effects produced by this tone were—long wave ultraviolet, a very strong bright yellow followed by a very strong greenish phosphorescence; short wave ultraviolet, a strong and bright yellow/green followed by a very strong greenish phosphorescence; and X-rays, a blue/green followed by a strong green phosphorescence.
Euclase
Chemistry: Berylium aluminum silicate
Crystal system: Monoclinic; prisms with numerous smooth faces; tabular, well developed.
Color: Transparent; colorless, pale green, light blue, sapphire blue (rare); may be color zoned
Hardness: 7.5
Cleavage: Perfect: 1 direction; Fracture: brittle, conchoidal to uneven.
Specific gravity: 3.10
Refractive index: 1.652 – 1.672; Biaxial positive; 0.02
Luster: Vitreous.
Dispersion: Low.
Dichroism: Weak.
Occurrence: Russia, Africa, Brazil.
Notes
Collector’s stone; name refers to its easy cleavage; may look like aquamarine and green spodumene, but D.R and S.G different; spectra in deep colors: 2 vague bands in blue 468 and 455nm, may also show line in red 705nm; difficult to cut; faceted.
Crystal system: Monoclinic; prisms with numerous smooth faces; tabular, well developed.
Color: Transparent; colorless, pale green, light blue, sapphire blue (rare); may be color zoned
Hardness: 7.5
Cleavage: Perfect: 1 direction; Fracture: brittle, conchoidal to uneven.
Specific gravity: 3.10
Refractive index: 1.652 – 1.672; Biaxial positive; 0.02
Luster: Vitreous.
Dispersion: Low.
Dichroism: Weak.
Occurrence: Russia, Africa, Brazil.
Notes
Collector’s stone; name refers to its easy cleavage; may look like aquamarine and green spodumene, but D.R and S.G different; spectra in deep colors: 2 vague bands in blue 468 and 455nm, may also show line in red 705nm; difficult to cut; faceted.
Tuesday, July 17, 2007
Shell Game Pilot
Memorable quotes from the movie:
Dinah (Margot Kidder): I was in Bogota, and I stumbled over this jerk drug dealer named Pavon, and... he just looked like he deserved to be taken, so... I sold him the Marie Antoinette diamonds.
Riley (James Read): You're still selling the Antoinettes? Those - those earrings were over-exposed years ago!
Dinah (Margot Kidder): In Europe, not in South America! It's a whole new market!
Riley (James Read): So what happened?
Dinah (Margot Kidder): Well, Pavon gave 'em to his girlfriend, and - and before she got 'em outta the box, she yelled, "Cubic zirconia..."
Dinah (Margot Kidder): I was in Bogota, and I stumbled over this jerk drug dealer named Pavon, and... he just looked like he deserved to be taken, so... I sold him the Marie Antoinette diamonds.
Riley (James Read): You're still selling the Antoinettes? Those - those earrings were over-exposed years ago!
Dinah (Margot Kidder): In Europe, not in South America! It's a whole new market!
Riley (James Read): So what happened?
Dinah (Margot Kidder): Well, Pavon gave 'em to his girlfriend, and - and before she got 'em outta the box, she yelled, "Cubic zirconia..."
Surviving The World Of Wine Etiquette
(via Indiatimes News Network) Reshmi R Dasgupta writes about the arcane world of wine etiquette @ http://economictimes.indiatimes.com/Surviving_the_world_of_wine_etiquette_/articleshow/2203459.cms
A Proper Temple
Economist writes about Indian modern art + Kolkata Museum of Modern Art, or KMoMA + other viewpoints @ http://www.economist.com/displayStory.cfm?story_id=9495928&fsrc=RSS
Tycoon Turf
(via The Irrawaddy) Aung Zaw writes about today's Burma + the two groups of people that govern the country + other viewpoints @ http://www.irrawaddy.org/article.php?art_id=5010
Coveting The Colored
Idexonline writes about colored diamonds + the way colored diamond dealers describe their stones + their scarcity and beauty + why the jewelers spend their lifetime hoping to hold and caress one of these extraordinary gems + other viewpoints @ http://www.idexonline.com/portal_FullMazalUbracha.asp?id=22694
The Pleasures Of Discovery
(via The Journal of Gemmology, Vol.XIV, No.3, July 1974) B W Anderson writes:
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
Ekanite
For the last of my stones we return to the gem gravels of Ceylon, and once more it was a keen gemologist who set the ball rolling. This was Mr F L D Ekanayake of Colombo, Ceylon, who, in 1953, sent a round cabochon dark green stone showing a faint four-rayed asterism to his friend, Mr R K Mitchell, accompanied by a letter in which he stated ‘I am sure this is a new mineral’. After some preliminary work Mr Mitchell allowed us to try our hand at solving the mystery of this peculiar stone. It appeared to be quite amorphous not only optically but to an X-ray beam, and yet the tiny oriented needles to which the asterism was due argued some degree of crystallinity. The density was 3.28 and R.I 1.60.
An attempt at spectrum analysis in the laboratory showed the presence of calcium, silica, and traces of lead. This last made me think in terms of glass, and I sent the stone to D K Hill, a well-known glass technologist, for his opinion. He at first confirmed the glass hypothesis, but then discovered by a much more skilled spectrum analysis than we could muster, that thorium was a major constituent of the material. Hill’s estimate was about 26 or 27% thorium oxide—which later proved to be almost exactly correct. On hearing this news the penny dropped, and I realized that we are dealing with a metamict—a crystal the structure of which had broken down due to 600 million years or so of internal bombardment with alpha particles, as in the case of the green metamict zircons we already knew so well. The trace of lead was also explained—this was the end product of the disintegration of thorium.
During this prolonged investigation, by another of those extraordinary chances of which I have already spoken, Mr Solomon, who was at the time an instructor of students of gemology in Plymouth, sent me a cabochon stone of this same metamict mineral, asking if I could tell what it was since it had puzzled his students. When I told him the story he kindly gave me the specimen.
As one could expect, Ekanayake’s stone proved to be quite strongly radioactive, leaving a trace after being placed on a photographic film for a few hours. Using a slice taken from the stone, we tried to return it to its original crystalline state by heat treatment: but heating at 1000ºC failed to bring about the hoped for alteration and transformed the stone into an opaque putty-colored mass.
It was several years before the Museum could proceed with the necessary complete analysis, which entailed a formidable piece of work and in the meantime Ekayanake had recovered three further pieces of the mineral from the same gem pit where the original was found—at Eheliyagoda near Ratnapura.
The final analyis, carried out by D I Bothwell, showed the new mineral to be essentially a silicate of thorium and calcium, though about 2% of uranium was also present. A preliminary note was published in Nature on June 10th, 1961, establishing the new mineral at last, and appropriately honoring its discoverer in the name Ekanite. R K Mitchell gave an excellent account of the long drawn out investigation in the Journal of Gemmology, and shortly afterwards Dr Edward Gubelin who, unknown to us, had been working intensively on the new mineral, of which he had acquired no fewer than 12 specimens, published a long and brilliant paper on the subject in Gems and Gemology, The Gemmologist, and elsewhere, which precluded the need for any further work on our part.
Since that time, crystallized forms of ekanite have been reported from Central Asia by Russian workers and from Saint-Hilaire, Quebec Province, in pegmatite veins. The crystals are tetragonal. The reason for these not having been reduced to the metamict stage lies in their much younger geological age—60 million years against 600 million.
One thing that took away much of the pleasure from these investigations into new gem minerals was the long delay between the initial burst of ordinary gemological work on the stones and the final necessary chemical analysis and crystal structure analysis which had to be performed before the mineral could be properly established and the conclusions published a scientific paper. One could not very well press for speed from the skilled Museum workers, for work which involved a great deal of time and effort, which had to be added to their own research programmes and routine work for the department. And we ourselves in the laboratory found it increasingly hard to find time to work continuously on any project as the demands of essential daily testing work became more and more pressing. Visits to the library became lunch-time snatches, and one felt guilty in doing any work which could be termed purely academic. And most of you know how hard it is to pick up the threads of any piece of work which has been put on a shelf and allowed to grow cold.
Amongst the advantages of such pieces of research are the sharpening of technical skills, an increased international reputation for the laboratory and a closer liaison with mineralogists—a liaison which is vital in the present state of our science.
For those of you who have found my topic for this evening too remote from everyday experiences and problems in the trade to interest you, I can promise a thoroughly down-to-earth talk next October, when I understand that I am going to be allowed to speak to you again.
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
Ekanite
For the last of my stones we return to the gem gravels of Ceylon, and once more it was a keen gemologist who set the ball rolling. This was Mr F L D Ekanayake of Colombo, Ceylon, who, in 1953, sent a round cabochon dark green stone showing a faint four-rayed asterism to his friend, Mr R K Mitchell, accompanied by a letter in which he stated ‘I am sure this is a new mineral’. After some preliminary work Mr Mitchell allowed us to try our hand at solving the mystery of this peculiar stone. It appeared to be quite amorphous not only optically but to an X-ray beam, and yet the tiny oriented needles to which the asterism was due argued some degree of crystallinity. The density was 3.28 and R.I 1.60.
An attempt at spectrum analysis in the laboratory showed the presence of calcium, silica, and traces of lead. This last made me think in terms of glass, and I sent the stone to D K Hill, a well-known glass technologist, for his opinion. He at first confirmed the glass hypothesis, but then discovered by a much more skilled spectrum analysis than we could muster, that thorium was a major constituent of the material. Hill’s estimate was about 26 or 27% thorium oxide—which later proved to be almost exactly correct. On hearing this news the penny dropped, and I realized that we are dealing with a metamict—a crystal the structure of which had broken down due to 600 million years or so of internal bombardment with alpha particles, as in the case of the green metamict zircons we already knew so well. The trace of lead was also explained—this was the end product of the disintegration of thorium.
During this prolonged investigation, by another of those extraordinary chances of which I have already spoken, Mr Solomon, who was at the time an instructor of students of gemology in Plymouth, sent me a cabochon stone of this same metamict mineral, asking if I could tell what it was since it had puzzled his students. When I told him the story he kindly gave me the specimen.
As one could expect, Ekanayake’s stone proved to be quite strongly radioactive, leaving a trace after being placed on a photographic film for a few hours. Using a slice taken from the stone, we tried to return it to its original crystalline state by heat treatment: but heating at 1000ºC failed to bring about the hoped for alteration and transformed the stone into an opaque putty-colored mass.
It was several years before the Museum could proceed with the necessary complete analysis, which entailed a formidable piece of work and in the meantime Ekayanake had recovered three further pieces of the mineral from the same gem pit where the original was found—at Eheliyagoda near Ratnapura.
The final analyis, carried out by D I Bothwell, showed the new mineral to be essentially a silicate of thorium and calcium, though about 2% of uranium was also present. A preliminary note was published in Nature on June 10th, 1961, establishing the new mineral at last, and appropriately honoring its discoverer in the name Ekanite. R K Mitchell gave an excellent account of the long drawn out investigation in the Journal of Gemmology, and shortly afterwards Dr Edward Gubelin who, unknown to us, had been working intensively on the new mineral, of which he had acquired no fewer than 12 specimens, published a long and brilliant paper on the subject in Gems and Gemology, The Gemmologist, and elsewhere, which precluded the need for any further work on our part.
Since that time, crystallized forms of ekanite have been reported from Central Asia by Russian workers and from Saint-Hilaire, Quebec Province, in pegmatite veins. The crystals are tetragonal. The reason for these not having been reduced to the metamict stage lies in their much younger geological age—60 million years against 600 million.
One thing that took away much of the pleasure from these investigations into new gem minerals was the long delay between the initial burst of ordinary gemological work on the stones and the final necessary chemical analysis and crystal structure analysis which had to be performed before the mineral could be properly established and the conclusions published a scientific paper. One could not very well press for speed from the skilled Museum workers, for work which involved a great deal of time and effort, which had to be added to their own research programmes and routine work for the department. And we ourselves in the laboratory found it increasingly hard to find time to work continuously on any project as the demands of essential daily testing work became more and more pressing. Visits to the library became lunch-time snatches, and one felt guilty in doing any work which could be termed purely academic. And most of you know how hard it is to pick up the threads of any piece of work which has been put on a shelf and allowed to grow cold.
Amongst the advantages of such pieces of research are the sharpening of technical skills, an increased international reputation for the laboratory and a closer liaison with mineralogists—a liaison which is vital in the present state of our science.
For those of you who have found my topic for this evening too remote from everyday experiences and problems in the trade to interest you, I can promise a thoroughly down-to-earth talk next October, when I understand that I am going to be allowed to speak to you again.
Epidote
Chemistry: Calcium aluminum silicate
Crystal system: Monoclinic; prism; deep vertical striations; seldom with distinct terminations.
Color: Transparent to translucent; Epidote: yellow, green, greenish (pistachio) brown; Clinozoisite: (low iron content) light green of greenish brown; red also known; Unakite: type of granite rock, mottled green, pink and gray.
Hardness: 6 - 7
Cleavage: Perfect: basal; Fracture: splintery, conchoidal.
Specific gravity: 3.28
Refractive index: 1.736 – 1770; Biaxial positive; Clinozoisite: 1.724 – 1.7324; Unakite: 1.52 – 1.76; 0.036 (may be lower 0.010)
Luster: Vitreous to metallic.
Dispersion: Medium
Dichroism: Strong: green, brown, yellow; chrome-light green/dark green.
Occurrence: Metamorphic and igneous; Mexico, Mozambique, Norway, USA, Austria; Unakite: South Africa, USA, Zimbabwe.
Notes
Closely related to zoisite; epidote group: zoisite and clinozoisite, epidote, piedmonite, hancockite, thulite (pink zoisite); unakite: ornamental rock containing quartz, pink feldspar and green epidote; intense band at 455nm or none depending on direction; also spectral band at 475nm; difficult to cut, faceted; unakite: beads and carvings.
Crystal system: Monoclinic; prism; deep vertical striations; seldom with distinct terminations.
Color: Transparent to translucent; Epidote: yellow, green, greenish (pistachio) brown; Clinozoisite: (low iron content) light green of greenish brown; red also known; Unakite: type of granite rock, mottled green, pink and gray.
Hardness: 6 - 7
Cleavage: Perfect: basal; Fracture: splintery, conchoidal.
Specific gravity: 3.28
Refractive index: 1.736 – 1770; Biaxial positive; Clinozoisite: 1.724 – 1.7324; Unakite: 1.52 – 1.76; 0.036 (may be lower 0.010)
Luster: Vitreous to metallic.
Dispersion: Medium
Dichroism: Strong: green, brown, yellow; chrome-light green/dark green.
Occurrence: Metamorphic and igneous; Mexico, Mozambique, Norway, USA, Austria; Unakite: South Africa, USA, Zimbabwe.
Notes
Closely related to zoisite; epidote group: zoisite and clinozoisite, epidote, piedmonite, hancockite, thulite (pink zoisite); unakite: ornamental rock containing quartz, pink feldspar and green epidote; intense band at 455nm or none depending on direction; also spectral band at 475nm; difficult to cut, faceted; unakite: beads and carvings.
Monday, July 16, 2007
The Wheeler Dealers
Memorable quote (s) from the movie:
Feinberg, Taxi Driver (Robert Strauss): You're just like my wife, mister. You don't understand the economics of the situation.
Henry Tyroon (James Garner): Then teach me. I'm interested in the economics of about every situation.
Feinberg, Taxi Driver (Robert Strauss): Well, there are 11,000 cabs in the city - and no new permits for the next twenty-five years. Now suppose you wanna buy a cab and start hackin'... you gotta get a new permit, too. Now the tab on a new permit is eighteen thousand five hundred on the open market.
Henry Tyroon (James Garner): And how much did your cab cost, Mister, Feinberg?
Feinberg, Taxi Driver (Robert Strauss): Thirty-three hundred... new.
Henry Tyroon (James Garner): Mm-hmm. Then that makes your investment, uh, with the permit, come to about $22,000.
Feinberg, Taxi Driver (Robert Strauss): Yeah. But don't tell my wife... she'll think I'm rich.
Henry Tyroon (James Garner): Mm-hmm. Mr. Feinberg, I'll give you $24,000 for your cab and permit.
Feinberg, Taxi Driver (Robert Strauss): You wanna buy the cab?
Henry Tyroon (James Garner): Right. But you come along with it. I'll need your services for a week, maybe two.
Feinberg, Taxi Driver (Robert Strauss): No, look, mister, I can't sell the cab. I need it.
Henry Tyroon (James Garner): Well, I figured that. So, when I leave I'll sell it back to you for... $22,000.
Feinberg, Taxi Driver (Robert Strauss): You wanna lose two grand just to keep your feet dry when it starts to rain?
Henry Tyroon (James Garner): I don't lose, Mr. Feinberg. See, I borrow the money and then I get a deduction on the loan interest and another on the depreciation and another on the loss when I sell it back to you. And you make a nice profit.
Feinberg, Taxi Driver (Robert Strauss): You win and I win. Uh-uh, there's gotta be a loser somewhere.
Henry Tyroon (Robert Garner): Taxman loses. He usually does on a Henry Tyroon deal.
Feinberg, Taxi Driver (Robert Strauss): Mister, you've just got yourself a taxi.
Feinberg, Taxi Driver (Robert Strauss): You're just like my wife, mister. You don't understand the economics of the situation.
Henry Tyroon (James Garner): Then teach me. I'm interested in the economics of about every situation.
Feinberg, Taxi Driver (Robert Strauss): Well, there are 11,000 cabs in the city - and no new permits for the next twenty-five years. Now suppose you wanna buy a cab and start hackin'... you gotta get a new permit, too. Now the tab on a new permit is eighteen thousand five hundred on the open market.
Henry Tyroon (James Garner): And how much did your cab cost, Mister, Feinberg?
Feinberg, Taxi Driver (Robert Strauss): Thirty-three hundred... new.
Henry Tyroon (James Garner): Mm-hmm. Then that makes your investment, uh, with the permit, come to about $22,000.
Feinberg, Taxi Driver (Robert Strauss): Yeah. But don't tell my wife... she'll think I'm rich.
Henry Tyroon (James Garner): Mm-hmm. Mr. Feinberg, I'll give you $24,000 for your cab and permit.
Feinberg, Taxi Driver (Robert Strauss): You wanna buy the cab?
Henry Tyroon (James Garner): Right. But you come along with it. I'll need your services for a week, maybe two.
Feinberg, Taxi Driver (Robert Strauss): No, look, mister, I can't sell the cab. I need it.
Henry Tyroon (James Garner): Well, I figured that. So, when I leave I'll sell it back to you for... $22,000.
Feinberg, Taxi Driver (Robert Strauss): You wanna lose two grand just to keep your feet dry when it starts to rain?
Henry Tyroon (James Garner): I don't lose, Mr. Feinberg. See, I borrow the money and then I get a deduction on the loan interest and another on the depreciation and another on the loss when I sell it back to you. And you make a nice profit.
Feinberg, Taxi Driver (Robert Strauss): You win and I win. Uh-uh, there's gotta be a loser somewhere.
Henry Tyroon (Robert Garner): Taxman loses. He usually does on a Henry Tyroon deal.
Feinberg, Taxi Driver (Robert Strauss): Mister, you've just got yourself a taxi.
Messaging Is The Medium
Daving Ng writes about The Sims: In The Hands of Artists concept + student art work (s) based on games + the way technology facilitates to create superb imageries + other viewpoints @ http://www.artnewsonline.com/issues/article.asp?art_id=2316
Romance Killer
Victoria Murphy writes about Mark Vadon, the boy from Seattle + his BlueNile.com concept + tips on dealing in diamonds + other viewpoints @ http://www.forbes.com/free_forbes/2004/1129/097.html
Colors Are A Girl's Best Friend
(via Newsweek International) Anna Kuchment writes about the growing interest in colored diamonds + the promotional launch of its first collection of colored stones by the online merchant BlueNile.com + other viewpoints @ http://www.msnbc.msn.com/id/19650872/site/newsweek
Jewelry Top Investment Of Passion
According to World Wealth Report (Merrill Lynch + Capgemini), for high net worth individuals, jewelry falls into the third category for investments of passion.
More info @ http://www.us.capgemini.com/worldwealthreport07/wwr_pressrelease.asp?ID=629
More info @ http://www.us.capgemini.com/worldwealthreport07/wwr_pressrelease.asp?ID=629
The Pleasures Of Discovery
(via The Journal of Gemmology, Vol.XIV, No.3, July 1974) B W Anderson writes:
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
Sinhalite
Less than a year after the paper on taaffeite was read before the Mineralogical Society, Dr Claringbull was able to announce the establishment of yet another new gem mineral, which he named sinhalite from its origin in Ceylon. But on this occasion we were spectators rather than protagonists, though we were able to provide many specimens to aid the work, as sinhalite had been knocking around for sometime under the disguise of brown peridot. Robert Webster indeed nobly sacrificed part of his only specimen for Dr Hey to analyze. Whereas, when the taaffeite paper was read, all we had to show was two small cut specimens, Claringbull had a score of sinhalites to show (one giant of 75 carats) which had crept from their wrongly labeled packets for the occasion. There was even a small pebble of sinhalite which had been picked from a sample of illam by Dr E H Rutland.
Credit for the sinhalite discovery belongs properly to Dr George Switzer of the Smithsonian Institution, who took an X-ray powder photograph of scrapings from the girdle of a ‘brown peridot’ in the U.S Museum collection and found spacings which clearly differed from those of olivine. Knowing this, Dr W F Foshag (Switzer’s chief in the Institution) cast doubts on a specimen of ‘brown peridot’ in the Natural History Museum when Dr Claringbull was showing him round the mineral gallery, which gave rise to an energetic attack on the problem.
Sinhalite contains no silica, being a magnesium alumunium borate, MgAlBO4. Like peridot, it is orthorhombic, and its refractive indices, birefringence and density are very close to those of brown iron-rich peridots or olivines which are occasionally met with in Arizona and elsewhere; the chief difference being in the b index, which in peridot is nearly mid-way between the greatest and least indices, while sinhalite is clearly negative in sign. The absorption spectra are also very similar in the two minerals, but sinhalite shows an extra band at 4630 Angstrom. Sinhalites have been found in packets of golden zircons and of yellow chrysoberyls—they vary in color from pale straw yellow, but at their best are very attractive, being clean, transparent, and obtainable in important sizes. In fact, of all the newly discovered stones that I am talking about this evening sinhalite is the only one that has the slightest commercial importance. On the ‘anything you can do’ principle which I mentioned earlier, it was Burma which provided the first well-shaped sinhalite crystal, which C J Payne had the privilege of measuring.
Painite
In painite we have the rarest mineral of them all: in fact I find it rather amusing, considering that no cut stone exists (2007: today there are cut specimens available at affordable prices ), that a description of the stone occurs in at least five books on gemstones. The original dark red crystal, well-formed though rather waterworn, was found in one of the small ruby mines near Ohngaing village in the Mogok district of Burma. Mr A C D Pain, who suspected it might be something new, sent it to the laboratory for testing. The crystal at first sight looked as though it were tetragonal, but C J Payne, finding the prism angles to be exactly 60º realized that in fact it was hexagonal. It weighed 8.5 carats. The density was found to be 4.01 and the refractive indices 1.8159 for the ordinary and 1.7875 for the extraordinary ray, giving a birefringence of 0.0284. The hardness was measured as 8 on Moh’s scale by an indentation method. The dichroism showed a brownish red for the ordinary ray and deep ruby red for the extraordinary.
Permission was given for a thin slice to be removed from the base of the crystal for Claringbull and Hey to carry out the necessary X-ray and chemical work. Analysis showed the mineral to be borosilicate of calcium and aluminium, but it proved difficult to ascribe to it a definite formula. The specimen was justly named after its discoverer, and presented by him to the Museum where most of the work on it was done.
Chromium lines were visible in the red end of the spectrum, and the color was probably due to this, at least in part. In confirmation of this, the stone showed a red glow under crossed filters. It is difficult to judge how attractive a cut painite might be. In bulk, the color was too deep to be effective, but one might guess that small stones might look very much like Siam rubies.
The Pleasure Of Discovery (continued)
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
Sinhalite
Less than a year after the paper on taaffeite was read before the Mineralogical Society, Dr Claringbull was able to announce the establishment of yet another new gem mineral, which he named sinhalite from its origin in Ceylon. But on this occasion we were spectators rather than protagonists, though we were able to provide many specimens to aid the work, as sinhalite had been knocking around for sometime under the disguise of brown peridot. Robert Webster indeed nobly sacrificed part of his only specimen for Dr Hey to analyze. Whereas, when the taaffeite paper was read, all we had to show was two small cut specimens, Claringbull had a score of sinhalites to show (one giant of 75 carats) which had crept from their wrongly labeled packets for the occasion. There was even a small pebble of sinhalite which had been picked from a sample of illam by Dr E H Rutland.
Credit for the sinhalite discovery belongs properly to Dr George Switzer of the Smithsonian Institution, who took an X-ray powder photograph of scrapings from the girdle of a ‘brown peridot’ in the U.S Museum collection and found spacings which clearly differed from those of olivine. Knowing this, Dr W F Foshag (Switzer’s chief in the Institution) cast doubts on a specimen of ‘brown peridot’ in the Natural History Museum when Dr Claringbull was showing him round the mineral gallery, which gave rise to an energetic attack on the problem.
Sinhalite contains no silica, being a magnesium alumunium borate, MgAlBO4. Like peridot, it is orthorhombic, and its refractive indices, birefringence and density are very close to those of brown iron-rich peridots or olivines which are occasionally met with in Arizona and elsewhere; the chief difference being in the b index, which in peridot is nearly mid-way between the greatest and least indices, while sinhalite is clearly negative in sign. The absorption spectra are also very similar in the two minerals, but sinhalite shows an extra band at 4630 Angstrom. Sinhalites have been found in packets of golden zircons and of yellow chrysoberyls—they vary in color from pale straw yellow, but at their best are very attractive, being clean, transparent, and obtainable in important sizes. In fact, of all the newly discovered stones that I am talking about this evening sinhalite is the only one that has the slightest commercial importance. On the ‘anything you can do’ principle which I mentioned earlier, it was Burma which provided the first well-shaped sinhalite crystal, which C J Payne had the privilege of measuring.
Painite
In painite we have the rarest mineral of them all: in fact I find it rather amusing, considering that no cut stone exists (2007: today there are cut specimens available at affordable prices ), that a description of the stone occurs in at least five books on gemstones. The original dark red crystal, well-formed though rather waterworn, was found in one of the small ruby mines near Ohngaing village in the Mogok district of Burma. Mr A C D Pain, who suspected it might be something new, sent it to the laboratory for testing. The crystal at first sight looked as though it were tetragonal, but C J Payne, finding the prism angles to be exactly 60º realized that in fact it was hexagonal. It weighed 8.5 carats. The density was found to be 4.01 and the refractive indices 1.8159 for the ordinary and 1.7875 for the extraordinary ray, giving a birefringence of 0.0284. The hardness was measured as 8 on Moh’s scale by an indentation method. The dichroism showed a brownish red for the ordinary ray and deep ruby red for the extraordinary.
Permission was given for a thin slice to be removed from the base of the crystal for Claringbull and Hey to carry out the necessary X-ray and chemical work. Analysis showed the mineral to be borosilicate of calcium and aluminium, but it proved difficult to ascribe to it a definite formula. The specimen was justly named after its discoverer, and presented by him to the Museum where most of the work on it was done.
Chromium lines were visible in the red end of the spectrum, and the color was probably due to this, at least in part. In confirmation of this, the stone showed a red glow under crossed filters. It is difficult to judge how attractive a cut painite might be. In bulk, the color was too deep to be effective, but one might guess that small stones might look very much like Siam rubies.
The Pleasure Of Discovery (continued)
Ekanite
Chemistry: Metamict-Calcium thorium silicate
Crystal system: Amorphous from Tetragonal; usually micro crystals; rarely large.
Color: Transparent to translucent; metamict: green, yellow, light brown; crystalline: yellow-red; phenomena: may show 4-rayed star.
Hardness: 6.0 – 6.5
Cleavage: -
Specific gravity: 3.28
Refractive index: 1.597 metamict; SR.
Luster: Vitreous.
Dispersion: -
Dichroism: -
Occurrence: Gem gravels of Sri Lanka; some crystalline material found in Canada.
Notes
Found in 1953; mildly radioactive; may be cut as collector’s stone.
Crystal system: Amorphous from Tetragonal; usually micro crystals; rarely large.
Color: Transparent to translucent; metamict: green, yellow, light brown; crystalline: yellow-red; phenomena: may show 4-rayed star.
Hardness: 6.0 – 6.5
Cleavage: -
Specific gravity: 3.28
Refractive index: 1.597 metamict; SR.
Luster: Vitreous.
Dispersion: -
Dichroism: -
Occurrence: Gem gravels of Sri Lanka; some crystalline material found in Canada.
Notes
Found in 1953; mildly radioactive; may be cut as collector’s stone.
Sunday, July 15, 2007
200 Top Art Collectors
The Art News 200 top art collectors list @ http://www.artnewsonline.com/issues/article.asp?art_id=2311
European Commission May Reconsider Decision To Close SoC Investigations
Chaim Even-Zohar writes about European Commission's (EC) views regarding De Beers’ Supplier of Choice (SoC), background to the judgment + the impact + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp
Jewel Thieves Make Off With Huge Haul
(via ABC news) London thieves show up in Bentley, make off with millions worth of jewelry.
The victim: Graff Jewellers!
More info @ http://abcnews.go.com/International/wireStory?id=3368938
The victim: Graff Jewellers!
More info @ http://abcnews.go.com/International/wireStory?id=3368938
Who Is Smiling?
Economist writes:
Riches do not necessarily make happiness, but a poll of 130 countries by Gallup found more people in wealthy places (America, Europe, Japan, Saudi Arabia) consider themselves happy, while those in poor countries (in Africa especially) generally do not. A map of the results, therefore, looks rather like an income plot of the world. There are a few exceptions. Mid-income Costa Ricans and Venezuelans are among the happiest on the planet. Georgians and Armenians, although not terribly poor, are among the glummest.
More info @http://www.economist.com/daily/chartgallery/displaystory.cfm?story_id=9490466
Riches do not necessarily make happiness, but a poll of 130 countries by Gallup found more people in wealthy places (America, Europe, Japan, Saudi Arabia) consider themselves happy, while those in poor countries (in Africa especially) generally do not. A map of the results, therefore, looks rather like an income plot of the world. There are a few exceptions. Mid-income Costa Ricans and Venezuelans are among the happiest on the planet. Georgians and Armenians, although not terribly poor, are among the glummest.
More info @http://www.economist.com/daily/chartgallery/displaystory.cfm?story_id=9490466
The Pleasures Of Discovery
(via The Journal of Gemmology, Vol.XIV, No.3, July 1974) B W Anderson writes:
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
The war
When Munich made it clear that war must inevitably come, Payne joined the Territorial Army and was trained as a gunner, whilst I enrolled with the Auxiliary Fire Service in London. When war was declared Payne was called up at once and spent the next few years fighting with the Eighth Army, rejoining the laboratory in September, 1945, just in time to prevent my being totally submerged in a sea of pearl testing. I was able to carry on with such testing work as there was with the aid of Sgt Stelling, a stalwart commissionaire, who had been taken on for the holiday period but who stayed for the ‘duration’. Actually, after the initial shock of war and the London ‘blitz’, the amount of testing work became quite heavy for one person. The number of tests undertaken dropped from the 1938 figure of 776 to 531 in 1939 and 323 in 1940, but had risen to 782 in 1944 and to 1062 in 1945. It was in 1946 that the really great expansion began and we enlisted the help of Robert Webster and Alec Farn, which completed the ‘Phalanx of Four’ which coped with the strenuous testing work of the next 25 years.
I mustn’t dwell on those war years, as I want to carry on with the story of discovery of new gem minerals, but a few points perhaps may be worth recalling.
As a safety precaution, our committee had moved our valuable X-ray equipment to a basement belonging to Johnson, Matthey & Co in Poland Street. This made the testing of undrilled and part-drilled pearls a very time consuming business, as I had to go down to Poland Street to take the photographs, and then post back to the laboratory to develop them.
The laboratory had several ‘near misses’ with bombs and fire, with minor damage. On the worst occasion I was luckily fighting a fire nearby and obtained permission to see how things were in the lab. A large cupboard full of chemicals had fallen on its face, making a truly unwholeseome mess on the floor. All I could do at the time was to pick up the small bottle containing the spontaneously inflammable yellow phosphorus, which I could see glowing in the dark, and put it into a bucket of water to wait for the morrow. I also had to comfort as best I could our diminutive housekeeper and his tearful wife, who had been sleeping each under one of our endoscopes when the bomb fell, and awoke to find that the apparatus had fallen on and around their legs. It required a good deal of cannibalization from other endoscopes to get ours into working order again.
During this war period I was able to do some useful work on the classification of diamond absorption and fluorescence, the distinction between pyrope and red spinel, etc. I also became aware for the first time of the advantages of the Becke 2458 prism spectroscope for spotting purposes, and with its aid discovered the ‘difficult’ absorption spectrum of turquoise, which has
since proved extremely useful. But now I must resume my main narrative.
Taaffeite
The discovery of the new gem mineral Taaffeite reads like a gemological fairy tale. Count Taaffe, only son of the 12th Viscount Taaffe of Corran, Baron of Ballymote in County Sligo, Ireland, was born in Bohemia in 1898, and died in Dublin in 1967. He was the first of his family to be allowed to return to Ireland after its long exile in Bohemia and Austria. Taaffe was a keen amateur both of gemology and astronomy, and found it both profitable and interesting to peddle in gemstones. Amongst his sources for inexpensive stones were the boxes of addments which jewelers keep behind their counters, finding them useful for jobbing purposes. In October 1945 he spent some days looking through the boxes belong to a friendly jeweler, Mr Robert Dobbie, and paid him £14 for the stones which interested him, which were mostly broken out of jewelry: badly rubbed or chipped in many cases.
Taffee worked with meager equipment, but made very effective use of what he did possess. He had no refractometer and no accurate balance. His chief instrument was a Bausch and Lomb binocular microscope without a stage, giving a magnification of 21 diameters.
His first steps, to which he attached great importance, in tackling a mixed batch of stones such as the lot from Mr Dobbie, was to clean the stones very thoroughly and then divide them by eye into batches according to color. He then examined each stone very carefully, holding it in tongs an scrutinizing it from all angles over a sheet of white paper. The illumination was a flexible desk lamp with a 100 watt bulb.
The stone which, incredibly, was later found to belong to a new mineral species was amongst a group of violet, mauve, and lilac colored stones. These were mostly spinels, but the stone in question showed in certain directions distinct signs of double refraction. In his words, ‘every speck of dust on the back and every scratch appeared double, like on a badly wobbled snapshot’. Since, as we now know, the stone had a D.R of only 0.005 and weighed only 1.42 carats, this was a remarkably acute piece of observation. He confirmed that the stone was birefringent by a test between crossed nicols, took a remarkably good density measurement (the average of ten attempts, using a hand-held balance) and finally on November 1st he posted the stone to me at the laboratory with a covering letter: ‘This time a new riddle: what is this mauve stone? It seems to me to answer all the characteristics of spinel, yet it shows double refraction: doubling of facets visible under the Greenough, extinction when polarized, though with queer color effects. Could anomalous double refraction be so strong? R.I too high for topaz, too low for corundum. What is it?’
The stone as received weighed 1.419 carats. Its shape suggested that it had been cut in Ceylon. The refractive indices were 1.718 for the extraordinary ray and 1.723 for the ordinary ray—thus the stone was uniaxial negative. It gave a clear uniaxial interference figure through the table facet. The density as then determined by hydrostatic weighing in ethylene dibromide was 3.621—later corrected to 3.613 by our Clerici solution flotation method, using blue spinels as indicators, one slightly denser and the other a little less dense than the taaffeite. The absorption spectrum was weak, but resembled that of blue spinel very closely.
I replied to Count Taaffe on November 5th, stating our findings and asking permission to have an X-ray analysis made if possible without harming the stone.
Preliminary X-ray tests carried out by Dr Claringbull confirmed the optical indications that the stone could not be spinel. To enable more X-ray and chemical work to be carried out Count Taaffe courageously agreed to having first one slice and then another removed from the culet region, stipulating only that the remains of his historic little stone be returned to him as a faceted gem. This work most skillfully carried out by Charles Mathews Lapidaries Ltd, the stone being reduced first to 0.95 and then to 0.56 carat. With a little imagination one can appreciate Taaffe’s feelings, knowing that he had discovered something quite new to science, but with only one small specimen as the representative of the new species.
On small crushed fragments from the stone X-ray powder, rotation and oriented Laue photographs were taken, showing the mineral to be hexagonal and to belong to the hexagonal trapezohedral class of symmetry—a class to which only ‘high’ quartz (formed above 573ºC) is known to belong. Preliminary analysis showed the presence of magnesium, alumunium and beryllium, and the final analysis, which was not completed until 1951, and was carried out by Dr Hey on only 6.16 milligrams of material, gave the essential formula as MgO.BeO.2Al2O3—that is, intermediate in composition between spinel and chrysoberyl. The ‘Oscars’ were mounting up for taaffeite: it belonged to a very rare class of crystal symmetry; and it was the only mineral known to contain both beryllium and magnesium as essential constituents. Data for an artificial compound of similar composition which were published in 1946 showed only a rough resemblance to those for taaffeite.
Naturally we kept a sharp lookout for further specimens, and examined every pale mauve spinel we could lay our hands on with extreme care, but it was not until October 1949 that the second taaffeite came to light, the honor and credit falling to C J Payne. He was working rather late in the laboratory on an interesting collection of 104 stones (mostly from Ceylon) sent in by a dealer for a routine test. There were a number of green sapphires and pale blue spinels and one kornerupine, which served as a curtain-raiser for a pale mauve stone weighing 0.86 carat which gave what appeared to be a taaffeite reading on the refractrometer. This was confirmed by the observation of a uniaxial interference figure. Payne was naturally enormously excited by his discovery after four years of searching, and rang me up at Goldsmith’s Hall where Webster and I were attending at a Gemological Exhibition being held there. Next day I was on holiday in Devon and had to carry on some cautious haggling by telephone with Payne as intermediary. At any cost, we had to have that stone. By using the kornerupine as a stalking horse we were able to obtain the two stones for £20.
After publication of the taaffeite story in Nature, the gemological journals, and Mineralogical Magazine in 1951, keen gemologists the world over were on the lookout for further specimens, but taaffeite number three did not appear until Christmas Eve, 1957, when it was spotted in the New York Gem Laboratory by our friend Robert Crowningshield. A further ten years were to elapse before a fourth specimen was identified in America following an article on the subject by George Bruce in the Modern Jeweler. This was a ‘giant’ of 5.34 carats, and, surprisingly, dark brownish purple in color.
In 1963 came a report that crystals of the mineral up to 1cm in length had been found in the Hunnan Province of China, though not of gem quality, and specimens are to be seen in the Mineralogical Museum of the Academy of Sciences in Moscow. Since then, tiny green crystals found in the Musgrave Ranges of Central Australia were found to be a ‘polytype’ of taaffeite in which nine subcells instead of four make up the unit cell, giving threefold in place of sixfold symmetry to X-ray patterns. One day, I am sure, a pebble of taaffeite will be found in the Ceylon gem gravels.
Of the four cut taaffeites mentioned, the original specimen was purchased by Mr R K Mitchell after Taaffe’s death, together with other stones from his small collection; the stone discovered by Payne is where it should be—in the Natural History Museum in South Kensington—while the American stones are apparently both in the hands of a private collector, though one was on show for a year at the Smithsonian Institute in Washington.
(continued)
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
The war
When Munich made it clear that war must inevitably come, Payne joined the Territorial Army and was trained as a gunner, whilst I enrolled with the Auxiliary Fire Service in London. When war was declared Payne was called up at once and spent the next few years fighting with the Eighth Army, rejoining the laboratory in September, 1945, just in time to prevent my being totally submerged in a sea of pearl testing. I was able to carry on with such testing work as there was with the aid of Sgt Stelling, a stalwart commissionaire, who had been taken on for the holiday period but who stayed for the ‘duration’. Actually, after the initial shock of war and the London ‘blitz’, the amount of testing work became quite heavy for one person. The number of tests undertaken dropped from the 1938 figure of 776 to 531 in 1939 and 323 in 1940, but had risen to 782 in 1944 and to 1062 in 1945. It was in 1946 that the really great expansion began and we enlisted the help of Robert Webster and Alec Farn, which completed the ‘Phalanx of Four’ which coped with the strenuous testing work of the next 25 years.
I mustn’t dwell on those war years, as I want to carry on with the story of discovery of new gem minerals, but a few points perhaps may be worth recalling.
As a safety precaution, our committee had moved our valuable X-ray equipment to a basement belonging to Johnson, Matthey & Co in Poland Street. This made the testing of undrilled and part-drilled pearls a very time consuming business, as I had to go down to Poland Street to take the photographs, and then post back to the laboratory to develop them.
The laboratory had several ‘near misses’ with bombs and fire, with minor damage. On the worst occasion I was luckily fighting a fire nearby and obtained permission to see how things were in the lab. A large cupboard full of chemicals had fallen on its face, making a truly unwholeseome mess on the floor. All I could do at the time was to pick up the small bottle containing the spontaneously inflammable yellow phosphorus, which I could see glowing in the dark, and put it into a bucket of water to wait for the morrow. I also had to comfort as best I could our diminutive housekeeper and his tearful wife, who had been sleeping each under one of our endoscopes when the bomb fell, and awoke to find that the apparatus had fallen on and around their legs. It required a good deal of cannibalization from other endoscopes to get ours into working order again.
During this war period I was able to do some useful work on the classification of diamond absorption and fluorescence, the distinction between pyrope and red spinel, etc. I also became aware for the first time of the advantages of the Becke 2458 prism spectroscope for spotting purposes, and with its aid discovered the ‘difficult’ absorption spectrum of turquoise, which has
since proved extremely useful. But now I must resume my main narrative.
Taaffeite
The discovery of the new gem mineral Taaffeite reads like a gemological fairy tale. Count Taaffe, only son of the 12th Viscount Taaffe of Corran, Baron of Ballymote in County Sligo, Ireland, was born in Bohemia in 1898, and died in Dublin in 1967. He was the first of his family to be allowed to return to Ireland after its long exile in Bohemia and Austria. Taaffe was a keen amateur both of gemology and astronomy, and found it both profitable and interesting to peddle in gemstones. Amongst his sources for inexpensive stones were the boxes of addments which jewelers keep behind their counters, finding them useful for jobbing purposes. In October 1945 he spent some days looking through the boxes belong to a friendly jeweler, Mr Robert Dobbie, and paid him £14 for the stones which interested him, which were mostly broken out of jewelry: badly rubbed or chipped in many cases.
Taffee worked with meager equipment, but made very effective use of what he did possess. He had no refractometer and no accurate balance. His chief instrument was a Bausch and Lomb binocular microscope without a stage, giving a magnification of 21 diameters.
His first steps, to which he attached great importance, in tackling a mixed batch of stones such as the lot from Mr Dobbie, was to clean the stones very thoroughly and then divide them by eye into batches according to color. He then examined each stone very carefully, holding it in tongs an scrutinizing it from all angles over a sheet of white paper. The illumination was a flexible desk lamp with a 100 watt bulb.
The stone which, incredibly, was later found to belong to a new mineral species was amongst a group of violet, mauve, and lilac colored stones. These were mostly spinels, but the stone in question showed in certain directions distinct signs of double refraction. In his words, ‘every speck of dust on the back and every scratch appeared double, like on a badly wobbled snapshot’. Since, as we now know, the stone had a D.R of only 0.005 and weighed only 1.42 carats, this was a remarkably acute piece of observation. He confirmed that the stone was birefringent by a test between crossed nicols, took a remarkably good density measurement (the average of ten attempts, using a hand-held balance) and finally on November 1st he posted the stone to me at the laboratory with a covering letter: ‘This time a new riddle: what is this mauve stone? It seems to me to answer all the characteristics of spinel, yet it shows double refraction: doubling of facets visible under the Greenough, extinction when polarized, though with queer color effects. Could anomalous double refraction be so strong? R.I too high for topaz, too low for corundum. What is it?’
The stone as received weighed 1.419 carats. Its shape suggested that it had been cut in Ceylon. The refractive indices were 1.718 for the extraordinary ray and 1.723 for the ordinary ray—thus the stone was uniaxial negative. It gave a clear uniaxial interference figure through the table facet. The density as then determined by hydrostatic weighing in ethylene dibromide was 3.621—later corrected to 3.613 by our Clerici solution flotation method, using blue spinels as indicators, one slightly denser and the other a little less dense than the taaffeite. The absorption spectrum was weak, but resembled that of blue spinel very closely.
I replied to Count Taaffe on November 5th, stating our findings and asking permission to have an X-ray analysis made if possible without harming the stone.
Preliminary X-ray tests carried out by Dr Claringbull confirmed the optical indications that the stone could not be spinel. To enable more X-ray and chemical work to be carried out Count Taaffe courageously agreed to having first one slice and then another removed from the culet region, stipulating only that the remains of his historic little stone be returned to him as a faceted gem. This work most skillfully carried out by Charles Mathews Lapidaries Ltd, the stone being reduced first to 0.95 and then to 0.56 carat. With a little imagination one can appreciate Taaffe’s feelings, knowing that he had discovered something quite new to science, but with only one small specimen as the representative of the new species.
On small crushed fragments from the stone X-ray powder, rotation and oriented Laue photographs were taken, showing the mineral to be hexagonal and to belong to the hexagonal trapezohedral class of symmetry—a class to which only ‘high’ quartz (formed above 573ºC) is known to belong. Preliminary analysis showed the presence of magnesium, alumunium and beryllium, and the final analysis, which was not completed until 1951, and was carried out by Dr Hey on only 6.16 milligrams of material, gave the essential formula as MgO.BeO.2Al2O3—that is, intermediate in composition between spinel and chrysoberyl. The ‘Oscars’ were mounting up for taaffeite: it belonged to a very rare class of crystal symmetry; and it was the only mineral known to contain both beryllium and magnesium as essential constituents. Data for an artificial compound of similar composition which were published in 1946 showed only a rough resemblance to those for taaffeite.
Naturally we kept a sharp lookout for further specimens, and examined every pale mauve spinel we could lay our hands on with extreme care, but it was not until October 1949 that the second taaffeite came to light, the honor and credit falling to C J Payne. He was working rather late in the laboratory on an interesting collection of 104 stones (mostly from Ceylon) sent in by a dealer for a routine test. There were a number of green sapphires and pale blue spinels and one kornerupine, which served as a curtain-raiser for a pale mauve stone weighing 0.86 carat which gave what appeared to be a taaffeite reading on the refractrometer. This was confirmed by the observation of a uniaxial interference figure. Payne was naturally enormously excited by his discovery after four years of searching, and rang me up at Goldsmith’s Hall where Webster and I were attending at a Gemological Exhibition being held there. Next day I was on holiday in Devon and had to carry on some cautious haggling by telephone with Payne as intermediary. At any cost, we had to have that stone. By using the kornerupine as a stalking horse we were able to obtain the two stones for £20.
After publication of the taaffeite story in Nature, the gemological journals, and Mineralogical Magazine in 1951, keen gemologists the world over were on the lookout for further specimens, but taaffeite number three did not appear until Christmas Eve, 1957, when it was spotted in the New York Gem Laboratory by our friend Robert Crowningshield. A further ten years were to elapse before a fourth specimen was identified in America following an article on the subject by George Bruce in the Modern Jeweler. This was a ‘giant’ of 5.34 carats, and, surprisingly, dark brownish purple in color.
In 1963 came a report that crystals of the mineral up to 1cm in length had been found in the Hunnan Province of China, though not of gem quality, and specimens are to be seen in the Mineralogical Museum of the Academy of Sciences in Moscow. Since then, tiny green crystals found in the Musgrave Ranges of Central Australia were found to be a ‘polytype’ of taaffeite in which nine subcells instead of four make up the unit cell, giving threefold in place of sixfold symmetry to X-ray patterns. One day, I am sure, a pebble of taaffeite will be found in the Ceylon gem gravels.
Of the four cut taaffeites mentioned, the original specimen was purchased by Mr R K Mitchell after Taaffe’s death, together with other stones from his small collection; the stone discovered by Payne is where it should be—in the Natural History Museum in South Kensington—while the American stones are apparently both in the hands of a private collector, though one was on show for a year at the Smithsonian Institute in Washington.
(continued)
Dumortierite
Chemistry: Aluminum boro-silicate
Crystal system: Orthorhombic; crystals rare; usually massive fibrous or columnar aggregates.
Color: Opaque; dark blue, blue, violet, brown/red.
Hardness: 7.0 – 8.5
Cleavage: Perfect; Fracture: conchoidal.
Specific gravity: 3.26 – 3.41
Refractive index: 1.686 – 1.723 (blurred, often intergrown with quartz will give quartz reading); 0.037
Luster: Vitreous to dull.
Dispersion: -
Dichroism: Strong; brown, orange, red.
Occurrence: Metamorphic and pegmatites; Brazil, Sri Lanka, Canada, Namibia, France, Madagascar, Poland.
Notes
Ornamental material; much gem Durmortierite is intergrown with quartz; for red/brown higher physical properties; may look like lapis lazuli, sodalite and azurite; weak but variable fluorescence; usually cut cabochon, beads and carvings.
Crystal system: Orthorhombic; crystals rare; usually massive fibrous or columnar aggregates.
Color: Opaque; dark blue, blue, violet, brown/red.
Hardness: 7.0 – 8.5
Cleavage: Perfect; Fracture: conchoidal.
Specific gravity: 3.26 – 3.41
Refractive index: 1.686 – 1.723 (blurred, often intergrown with quartz will give quartz reading); 0.037
Luster: Vitreous to dull.
Dispersion: -
Dichroism: Strong; brown, orange, red.
Occurrence: Metamorphic and pegmatites; Brazil, Sri Lanka, Canada, Namibia, France, Madagascar, Poland.
Notes
Ornamental material; much gem Durmortierite is intergrown with quartz; for red/brown higher physical properties; may look like lapis lazuli, sodalite and azurite; weak but variable fluorescence; usually cut cabochon, beads and carvings.
Saturday, July 14, 2007
The Offer-You-Can’t-Refuse Market
Milton Esterow writes about the art market + the characters behind the purchases + the importance of private markets (than the auction markets) + other viewpoints @ http://www.artnewsonline.com/issues/article.asp?art_id=2310
Indonesian Art: The Undercutting Edge
Jason Tedjasukmana writes about the talented Indonesian artists + the extraordinary value in comparison to the record-breaking sums trading hands at Asian art auctions + other viewpoints @ http://www.time.com/time/magazine/article/0,9171,1642682,00.html
George Melly
The Economist writes:
.....but Mr Melly liked fishing for another reason. As a lifelong Surrealist, he was sure that the bizarre and marvellous lay in wait for him everywhere, and carried in his head a Surrealist motto, “the certainty of chance”. Chance might give him a fish with the next cast; and chance shaped his drifting, exuberant, deep-drinking life, from Stowe to the wartime navy to art-dealing to journalism on the Observer, through a rich cast of queens, hoodlums, sailors, old trouts, whores and martinets, until in 1974 the career of a risqué jazz singer finally hooked him for good.
More info @ http://www.economist.com/obituary/displaystory.cfm?story_id=9467099
Alan George Heywood Melly, jazzman and writer, was Britain's most outrageous jazz singer + a tranquil fisherman. Think for a moment. Certainity of chance might/should work in other faculties of life too, like finding a new gem deposit, flawless, near flawless diamonds, rubies, blue sapphires + other colored stones, good men + women, business partner (s) and so on.....by the way, I do believe in the certainty of chance.
.....but Mr Melly liked fishing for another reason. As a lifelong Surrealist, he was sure that the bizarre and marvellous lay in wait for him everywhere, and carried in his head a Surrealist motto, “the certainty of chance”. Chance might give him a fish with the next cast; and chance shaped his drifting, exuberant, deep-drinking life, from Stowe to the wartime navy to art-dealing to journalism on the Observer, through a rich cast of queens, hoodlums, sailors, old trouts, whores and martinets, until in 1974 the career of a risqué jazz singer finally hooked him for good.
More info @ http://www.economist.com/obituary/displaystory.cfm?story_id=9467099
Alan George Heywood Melly, jazzman and writer, was Britain's most outrageous jazz singer + a tranquil fisherman. Think for a moment. Certainity of chance might/should work in other faculties of life too, like finding a new gem deposit, flawless, near flawless diamonds, rubies, blue sapphires + other colored stones, good men + women, business partner (s) and so on.....by the way, I do believe in the certainty of chance.
Africa First In Focus: Has It Got What It Needs To Succeed?
(Vol.3 Edition 7, June 2007) Antwerp Focus writes:
Observers note that, ironically, the first shot in what was supposed to be a revolutuion in the South African minerals sector was heard not at home, but in Belgium, at Antwerp Diamond Conference in November 2004. It was fired by President Thabo Mbeki, who was the guest of honor and keynote speaker at the conference’s gala dinner.
‘There is a widely shared view that all humanity should seek to make an impact on the globalization process so that it does not result in the marginalization and impoverishment of large numbers of people globally,’ Mbeki said. ‘With regard to our own continent, it is our firm view that this cannot be done on the basis of the pertuation of the old relationnship according to which we as colonies produced and exported raw materials and imported high vaue added manufactured goods from the colonizing countries.’
Thus was unveiled a policy that came to be known as ‘beneficiation’. It referred to a deliberate practice of preferential treatment for South African industry, with the goal being that a greater percentage of the country’s mineral output would be processed at home, thereby providing the domestic economy with an increased share of the added value that comes from further down the distribution pipeline.
‘From a jewelry perspective, it is common knowledge that South Africa is one of the richest countries in the world in mineral reserves, producing approximately 25% of all raw materials for worldwide jewelry production,’ explained Elizabeth Thabethe, South Africa’s Deputy Minister of Trade and Industry, in an address she delivered on March 12 to the 2007 CIBJO Congress in Cape Town. ‘But although South Africa is an exporter of jewelry, we contribute less than half a percent to the world’s fabricated jewelry market. There is growing recognition that South Africa must develop the means to transform its compartive advantage as a leading producer of precious metals and stones to become a globally competitive producer and marketer of jewelry.’
Initially, the international reaction to the South African government’s beneficiation policy was lukewarm at best. But a growing recognition among the leadership of the gemstone and jewelry sector that the industry needs to play a more proactive role in promoting sustainable economic social development in the producing countries has led to a general acceptance that the ‘Africa First’ approach has merit.
For the South African government, there is a link between economic development and longterm political stability. ‘We have more than 10 million young, unskilled people with 12 years and less of schooling to focus on in the short term,’ explained South Africa’s deputy president, Phumzile Mlambo-Ngcuka, in her address to the CIBJO Congress. ‘If our democracy is to work, it is with them, in the first place, with whom the growth must be shared.’
The government is vesting a great deal in beneficiation. It hopes that the policy will contribute to its achieving a level of GDP growth of 6 percent per annum by 2010. It it falls short, the post-apartheid honeymoon, which still has not completely ended, would definitely be over.
But members of the South African jewelry industry, while supportive of the beneficiation strategy, are nonethelss skeptical about its chances of success. ‘Don’t get me wrong, I would love for it to work out,’ said a jewelry manufacturer in Johannesburg. ‘But, as it is designed right now, I am not sure that it addresses our most basic concerns, and the world certainly is not waiting for us to catch up.’
Beneficiation is not simply a goal; it is being ensconced into law. The country’s new Minerals and Petroleum Resources Development Act, as well as recent amendments to the Diamond Act and chapter 16 of the Minerals Rights Act were, in the words of the South African Minerals and Energy Minister, Buyelwa Sonjica, ‘carrierd out to encourage wider participation, across race and gender, in both mining and beneficiation.’
A key element of the amended Diamond Act invovles the establishment of the State Diamond Trader, whose role it will be to acquire and distribute rough diamonds to local cutters and polishers. While the minister of Minerals and Energy is still scheduled to provide a detailed explanation of the functions and modus operandi of the State Diamond Trader, reportedly the new government agency will purchase 10 percent of South African rough output specifically for local beneficiation. Furthermore, the output of the government-owned Alexkor mine will be supplied to the State Diamond Trader, and De Beers transferring to the new government agency its local Diamdel infrastructure and personnel.
The amended Diamond Act also includesa tax on rough diamond exports, which at one stage was pegged 15 percent, but since has been reduced to a more moderate 5 percent. But, warned South African analyst James Allan, when he addressed a mainly local audience at the Diamonds Africa 2007 conference in Johannesburg on April 23, the export tax may have ‘unintended consequences’. While it certainly has the potential of creating between 400 and 500 additional jobs in the local cutting industry, as result of more rough remaining in the country, it may also have the effect of cutting rough diamond supplies by up to 30 percent and, ultimately, could lead to the loss of about 5000 mining jobs, Allan said. In his opinion, the pressures created by the addition of the 5 percent export tax could accelerate due to De Beer’s decision to close or sell the more marginal Cullinan, Namaqualand and Koffiefontein diamond mines.
Allan said that the local cutting industry can only be grown by reducing costs and improved productivity. He said that South African cutters find it very difficult to compete with India and China, when their cutting costs vary between $45 per carat and $100 per carat, whereas in India the costs are between $1 per carat and $8 per carat, and in China between $6 per carat and $12 per carat. For South Africa to become a major diamond beneficiation center, it would have to cut its production costs to no more than $20 per carat, he stated.
Despite the difficulties facing it, South Africa’s diamond cutting sector is still in better shape to impact the international marketplace than is the country’s jewelry manufacturing sector. The South African jewelry industry comprises 350 manufacturing companies, employing about 3000 people, although there may be up to 2500 manufacturers in the informal sector. Most of the jewelry sector’s output is geared to the local market, with only a handful of companies actively targeting overseas customers. In 2000, AngloGold—now AngloGold Ashanti—one of the world’s largest gold producers, acquired a 25 percent stake in OroAfrica, and began to cooperate with the company on a number of strategic marketing initiatives, including the establishment of a new product design center. The company exports a significant part of its output to the United States and Europe.
But, said Gary Nathan, OroAfrica’s managing director, while his company has shown that is possible for South Africans to penetrate and compete in foreign market, ‘we face a range of obstacles that severely hinder the development of an export oriented jewelry sector. If, for example, I was manufacturing in Italy and I needed findings, I could walk down the street to my supplier and buy exactly the amount that I require. Here, my options are to make them myself, or to order them from abroad. Right from the outset I am working at a disadvantage.’
In October 2000, AngloGold Ashanti and Rand Refinery initiated a ‘clustering’ project designed to assist jewelry manufacturers to export. Called the Gold Zone, it involved the establishment of a manufacturing enclosure on a 3.3 hectare plot provided by Rand Refinery, whose own facility is adjacent. Firms in the zone could not only benefit from low rental and maintenance costs, but also from the direct and secure supplies of gold from the refinery, and access to secure export facilities at OR Tambo International Airport in Johannesburg. To date, only one manufacturer—albeit one the country’s largest, Alan Mair Manufacturing Jewellers—was prepared to invest in building a factory in the Gold Zone.
Unlike other jewelry manufacturing centers, South Africa never developed an active bullion lending business, which would have enabled manufacturing jewelers to benefit from gold lending rates based on the gold lease rate, which is typically lower than monetary interest rates. Local jewelers had to rely on ordinary bank loan agreements for financing working gold inventory, and South Africa is a high interest rate country. Local jewelry manufacturers typically pay prime interest rates plus a 2-3 percent risk premium. Local manufacturers say that this makes their gold at least 6 percent more expensive than their competitors abroad.
The government has been looking for a solution. At the end of 2005, it initiated the launch of a 1000 kilogram gold advance scheme through a consortium that included European defense contractors Saab and BAE Systems, and gold mining companies AngloGold Ashanti and Gold Fields Limited, which collectively extended guarantees of $10.5 million to Standard Bank, which would underwrite the scheme.
For a variety of reasons the gold loan has to date been ineffectual, but it and other complementary programs continue to enjoy the strong support of government. ‘The jewelry industry, as a down stream industry, is ideally placed to contribute to job creation and economic growth,’ Deputy President Mlambo-Ngcuka, told the CIBJO Congress in March. ‘The industry is in large parts labor intensive and could be a contributor to social and economic development. We recognize direct jobs are not in millions but we welcome the thousands and the indirect jobs.’
Observers note that, ironically, the first shot in what was supposed to be a revolutuion in the South African minerals sector was heard not at home, but in Belgium, at Antwerp Diamond Conference in November 2004. It was fired by President Thabo Mbeki, who was the guest of honor and keynote speaker at the conference’s gala dinner.
‘There is a widely shared view that all humanity should seek to make an impact on the globalization process so that it does not result in the marginalization and impoverishment of large numbers of people globally,’ Mbeki said. ‘With regard to our own continent, it is our firm view that this cannot be done on the basis of the pertuation of the old relationnship according to which we as colonies produced and exported raw materials and imported high vaue added manufactured goods from the colonizing countries.’
Thus was unveiled a policy that came to be known as ‘beneficiation’. It referred to a deliberate practice of preferential treatment for South African industry, with the goal being that a greater percentage of the country’s mineral output would be processed at home, thereby providing the domestic economy with an increased share of the added value that comes from further down the distribution pipeline.
‘From a jewelry perspective, it is common knowledge that South Africa is one of the richest countries in the world in mineral reserves, producing approximately 25% of all raw materials for worldwide jewelry production,’ explained Elizabeth Thabethe, South Africa’s Deputy Minister of Trade and Industry, in an address she delivered on March 12 to the 2007 CIBJO Congress in Cape Town. ‘But although South Africa is an exporter of jewelry, we contribute less than half a percent to the world’s fabricated jewelry market. There is growing recognition that South Africa must develop the means to transform its compartive advantage as a leading producer of precious metals and stones to become a globally competitive producer and marketer of jewelry.’
Initially, the international reaction to the South African government’s beneficiation policy was lukewarm at best. But a growing recognition among the leadership of the gemstone and jewelry sector that the industry needs to play a more proactive role in promoting sustainable economic social development in the producing countries has led to a general acceptance that the ‘Africa First’ approach has merit.
For the South African government, there is a link between economic development and longterm political stability. ‘We have more than 10 million young, unskilled people with 12 years and less of schooling to focus on in the short term,’ explained South Africa’s deputy president, Phumzile Mlambo-Ngcuka, in her address to the CIBJO Congress. ‘If our democracy is to work, it is with them, in the first place, with whom the growth must be shared.’
The government is vesting a great deal in beneficiation. It hopes that the policy will contribute to its achieving a level of GDP growth of 6 percent per annum by 2010. It it falls short, the post-apartheid honeymoon, which still has not completely ended, would definitely be over.
But members of the South African jewelry industry, while supportive of the beneficiation strategy, are nonethelss skeptical about its chances of success. ‘Don’t get me wrong, I would love for it to work out,’ said a jewelry manufacturer in Johannesburg. ‘But, as it is designed right now, I am not sure that it addresses our most basic concerns, and the world certainly is not waiting for us to catch up.’
Beneficiation is not simply a goal; it is being ensconced into law. The country’s new Minerals and Petroleum Resources Development Act, as well as recent amendments to the Diamond Act and chapter 16 of the Minerals Rights Act were, in the words of the South African Minerals and Energy Minister, Buyelwa Sonjica, ‘carrierd out to encourage wider participation, across race and gender, in both mining and beneficiation.’
A key element of the amended Diamond Act invovles the establishment of the State Diamond Trader, whose role it will be to acquire and distribute rough diamonds to local cutters and polishers. While the minister of Minerals and Energy is still scheduled to provide a detailed explanation of the functions and modus operandi of the State Diamond Trader, reportedly the new government agency will purchase 10 percent of South African rough output specifically for local beneficiation. Furthermore, the output of the government-owned Alexkor mine will be supplied to the State Diamond Trader, and De Beers transferring to the new government agency its local Diamdel infrastructure and personnel.
The amended Diamond Act also includesa tax on rough diamond exports, which at one stage was pegged 15 percent, but since has been reduced to a more moderate 5 percent. But, warned South African analyst James Allan, when he addressed a mainly local audience at the Diamonds Africa 2007 conference in Johannesburg on April 23, the export tax may have ‘unintended consequences’. While it certainly has the potential of creating between 400 and 500 additional jobs in the local cutting industry, as result of more rough remaining in the country, it may also have the effect of cutting rough diamond supplies by up to 30 percent and, ultimately, could lead to the loss of about 5000 mining jobs, Allan said. In his opinion, the pressures created by the addition of the 5 percent export tax could accelerate due to De Beer’s decision to close or sell the more marginal Cullinan, Namaqualand and Koffiefontein diamond mines.
Allan said that the local cutting industry can only be grown by reducing costs and improved productivity. He said that South African cutters find it very difficult to compete with India and China, when their cutting costs vary between $45 per carat and $100 per carat, whereas in India the costs are between $1 per carat and $8 per carat, and in China between $6 per carat and $12 per carat. For South Africa to become a major diamond beneficiation center, it would have to cut its production costs to no more than $20 per carat, he stated.
Despite the difficulties facing it, South Africa’s diamond cutting sector is still in better shape to impact the international marketplace than is the country’s jewelry manufacturing sector. The South African jewelry industry comprises 350 manufacturing companies, employing about 3000 people, although there may be up to 2500 manufacturers in the informal sector. Most of the jewelry sector’s output is geared to the local market, with only a handful of companies actively targeting overseas customers. In 2000, AngloGold—now AngloGold Ashanti—one of the world’s largest gold producers, acquired a 25 percent stake in OroAfrica, and began to cooperate with the company on a number of strategic marketing initiatives, including the establishment of a new product design center. The company exports a significant part of its output to the United States and Europe.
But, said Gary Nathan, OroAfrica’s managing director, while his company has shown that is possible for South Africans to penetrate and compete in foreign market, ‘we face a range of obstacles that severely hinder the development of an export oriented jewelry sector. If, for example, I was manufacturing in Italy and I needed findings, I could walk down the street to my supplier and buy exactly the amount that I require. Here, my options are to make them myself, or to order them from abroad. Right from the outset I am working at a disadvantage.’
In October 2000, AngloGold Ashanti and Rand Refinery initiated a ‘clustering’ project designed to assist jewelry manufacturers to export. Called the Gold Zone, it involved the establishment of a manufacturing enclosure on a 3.3 hectare plot provided by Rand Refinery, whose own facility is adjacent. Firms in the zone could not only benefit from low rental and maintenance costs, but also from the direct and secure supplies of gold from the refinery, and access to secure export facilities at OR Tambo International Airport in Johannesburg. To date, only one manufacturer—albeit one the country’s largest, Alan Mair Manufacturing Jewellers—was prepared to invest in building a factory in the Gold Zone.
Unlike other jewelry manufacturing centers, South Africa never developed an active bullion lending business, which would have enabled manufacturing jewelers to benefit from gold lending rates based on the gold lease rate, which is typically lower than monetary interest rates. Local jewelers had to rely on ordinary bank loan agreements for financing working gold inventory, and South Africa is a high interest rate country. Local jewelry manufacturers typically pay prime interest rates plus a 2-3 percent risk premium. Local manufacturers say that this makes their gold at least 6 percent more expensive than their competitors abroad.
The government has been looking for a solution. At the end of 2005, it initiated the launch of a 1000 kilogram gold advance scheme through a consortium that included European defense contractors Saab and BAE Systems, and gold mining companies AngloGold Ashanti and Gold Fields Limited, which collectively extended guarantees of $10.5 million to Standard Bank, which would underwrite the scheme.
For a variety of reasons the gold loan has to date been ineffectual, but it and other complementary programs continue to enjoy the strong support of government. ‘The jewelry industry, as a down stream industry, is ideally placed to contribute to job creation and economic growth,’ Deputy President Mlambo-Ngcuka, told the CIBJO Congress in March. ‘The industry is in large parts labor intensive and could be a contributor to social and economic development. We recognize direct jobs are not in millions but we welcome the thousands and the indirect jobs.’
The Pleasures Of Discovery
(via The Journal of Gemmology, Vol.XIV, No.3, July 1974) B W Anderson writes:
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
Kornerupine
One thing leads to another. During our search for blue spinels of high refractive index in parcels of mixed Ceylon stones, we had come across a few specimens which we couldn’t identify. These were brownish green in color, had a density nearly matching that of methylene iodide (3.33) and refractive indices 1.670 – 1.683. They were strongly pleochroic from pale brown to dark green and had vague absorption bands in the blue and violet. We put them on one side in a packet, labeled ‘Y’, as we could find nothing in the tables of mineral properties to tally with these constants.
At that time I was very interested in the absorption spectrum of enstatite, since we had found that the attractive green pebbles from Kimberley showed a beautifully clear cut line 5600 Angstrom and I wanted to know whether specimens from other localities showed the same. The Natural History Museum had in their collection a cut stone weighing 9.18 carats, which had been rescued from an ‘idocrase’ box by Dr Herbert Smith on the basis of a refractometer test, and more plausibly labeled ‘enstatite’. I asked permission from then Keeper of Minerals, Dr L J Spencer, to examine the stone, and we found that it was not enstatite, but did tally closely in properties with our unknown ‘Y’ specimens. Naturally the Museum people were now interested, and Dr Claringbull by X-ray analysis was able to identify our unknowns as kornerupines of a hitherto unrecorded type. Previously the only gem quality kornerupines known were pale aquamarine-colored stones from Madagascar, containing less iron and with rather lower constants.
By one of those lucky and highly improbable chances with which we have been favored from time to time in our work, a mounted kornerupine of ‘our’ kind was sent to us for testing by a York jeweler. I was able to purchase the stone (which weighed 6.74 carats) for a reasonable price: the jeweler was very happy to replace it by a tourmaline rather than to try and sell a stone which had a name quite unknown to the public. A slice was removed from this for analysis, the recut stone weighing 3.50 carats.
Kornerupine is a complex borosilicate of aluminum, magnesium and iron, and the chemical analysis, undertaken by Dr Max Hey, was unusually difficult on a micro-scale, owning to the presence of boron, which several previous analysts had missed. For Dr Hey, this developed into a major piece of chemical research into the best methods for analysis of this difficult subject and a re-assessment of all previous analyses.
Meanwhile our main concern was to prove that these ‘new style’ kornerupines did in fact come from Ceylon, which we strongly suspected from the company they kept, by the style of cutting, and some of the inclusions. Through the kindness of Mr Hans Van Starrex we were sent two generous consignments of the gem gravel from Matale, and from the first of these, after about an hour’s search, we were delighted to find the first recorded kornerupine from the illam of Ceylon. Twenty minutes later another turned up—but in the second parcel there were none. My method was to segregate the pebbles of likely color, then quickly run through them with the spectroscope, eliminating all the zircons, which formed the bulk of the parcel. Any stones which seemed possibly to be kornerupine were passed to Mr Payne who examined them with a dichroscope and checked their density in methylene iodide, in which kornerupine remained virtually suspended.
The long chemical investigation naturally involved delay, and it was not until more than two years after the war had started that the full details were published. After the war, Mr Kenneth Parkinson, on one of his several successful visits to Ceylon in search of rare gemstones, returned with a cut kornerupine weighing 9.89 carats and a large piece of rough weighing 24.12 carats. This was unusual in showing traces of prism faces and is now in the collection of the Natural History Museum. And at about this time Dr E H Rutland sorted through some 15 lb. of illam provided by Mr Reggie Mathews, and was able to recover 8 kornerupines, which yielded cut stones ranging in size from 0.30 to 1.15 carats. These were mostly the usual brownish green, but some were distinctly green and one was yellow.
Before leaving kornerupine, let me say just a word about another ‘new’ occurrence of the mineral which we were the first to establish.
About 1937 we had acquired a small but very pretty green stone weighing 0.22 carat, which had refractive indices and density near those of the Ceylon kornerupines discussed above. After these had been identified by the Museum we realized that this stone, too, must be a kornerupine, but from some other source. Not until August 1952 did we know that this source must be the Mogok stone tract in Burma, for it was then that A C D Pain submitted for test a collection of interesting stones, all from Burma, amongst which was a bright green specimen with only the table facet polished, which we identified as kornerupine. The color, the inclusions and the properties were close enough to ours to make us sure that the origin was the same. It is curious how the jingle ‘anything you can do, I can do better’ seems to be appropriate when it comes to Burma versus the Ceylon gem fields.
The Pleasure Of Discovery (continued)
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
Kornerupine
One thing leads to another. During our search for blue spinels of high refractive index in parcels of mixed Ceylon stones, we had come across a few specimens which we couldn’t identify. These were brownish green in color, had a density nearly matching that of methylene iodide (3.33) and refractive indices 1.670 – 1.683. They were strongly pleochroic from pale brown to dark green and had vague absorption bands in the blue and violet. We put them on one side in a packet, labeled ‘Y’, as we could find nothing in the tables of mineral properties to tally with these constants.
At that time I was very interested in the absorption spectrum of enstatite, since we had found that the attractive green pebbles from Kimberley showed a beautifully clear cut line 5600 Angstrom and I wanted to know whether specimens from other localities showed the same. The Natural History Museum had in their collection a cut stone weighing 9.18 carats, which had been rescued from an ‘idocrase’ box by Dr Herbert Smith on the basis of a refractometer test, and more plausibly labeled ‘enstatite’. I asked permission from then Keeper of Minerals, Dr L J Spencer, to examine the stone, and we found that it was not enstatite, but did tally closely in properties with our unknown ‘Y’ specimens. Naturally the Museum people were now interested, and Dr Claringbull by X-ray analysis was able to identify our unknowns as kornerupines of a hitherto unrecorded type. Previously the only gem quality kornerupines known were pale aquamarine-colored stones from Madagascar, containing less iron and with rather lower constants.
By one of those lucky and highly improbable chances with which we have been favored from time to time in our work, a mounted kornerupine of ‘our’ kind was sent to us for testing by a York jeweler. I was able to purchase the stone (which weighed 6.74 carats) for a reasonable price: the jeweler was very happy to replace it by a tourmaline rather than to try and sell a stone which had a name quite unknown to the public. A slice was removed from this for analysis, the recut stone weighing 3.50 carats.
Kornerupine is a complex borosilicate of aluminum, magnesium and iron, and the chemical analysis, undertaken by Dr Max Hey, was unusually difficult on a micro-scale, owning to the presence of boron, which several previous analysts had missed. For Dr Hey, this developed into a major piece of chemical research into the best methods for analysis of this difficult subject and a re-assessment of all previous analyses.
Meanwhile our main concern was to prove that these ‘new style’ kornerupines did in fact come from Ceylon, which we strongly suspected from the company they kept, by the style of cutting, and some of the inclusions. Through the kindness of Mr Hans Van Starrex we were sent two generous consignments of the gem gravel from Matale, and from the first of these, after about an hour’s search, we were delighted to find the first recorded kornerupine from the illam of Ceylon. Twenty minutes later another turned up—but in the second parcel there were none. My method was to segregate the pebbles of likely color, then quickly run through them with the spectroscope, eliminating all the zircons, which formed the bulk of the parcel. Any stones which seemed possibly to be kornerupine were passed to Mr Payne who examined them with a dichroscope and checked their density in methylene iodide, in which kornerupine remained virtually suspended.
The long chemical investigation naturally involved delay, and it was not until more than two years after the war had started that the full details were published. After the war, Mr Kenneth Parkinson, on one of his several successful visits to Ceylon in search of rare gemstones, returned with a cut kornerupine weighing 9.89 carats and a large piece of rough weighing 24.12 carats. This was unusual in showing traces of prism faces and is now in the collection of the Natural History Museum. And at about this time Dr E H Rutland sorted through some 15 lb. of illam provided by Mr Reggie Mathews, and was able to recover 8 kornerupines, which yielded cut stones ranging in size from 0.30 to 1.15 carats. These were mostly the usual brownish green, but some were distinctly green and one was yellow.
Before leaving kornerupine, let me say just a word about another ‘new’ occurrence of the mineral which we were the first to establish.
About 1937 we had acquired a small but very pretty green stone weighing 0.22 carat, which had refractive indices and density near those of the Ceylon kornerupines discussed above. After these had been identified by the Museum we realized that this stone, too, must be a kornerupine, but from some other source. Not until August 1952 did we know that this source must be the Mogok stone tract in Burma, for it was then that A C D Pain submitted for test a collection of interesting stones, all from Burma, amongst which was a bright green specimen with only the table facet polished, which we identified as kornerupine. The color, the inclusions and the properties were close enough to ours to make us sure that the origin was the same. It is curious how the jingle ‘anything you can do, I can do better’ seems to be appropriate when it comes to Burma versus the Ceylon gem fields.
The Pleasure Of Discovery (continued)
Datolite
Chemistry: Calcium boro-silicate
Crystal system: Monoclinic; short prismatic crystals of varied habit; polycrystalline; massive.
Color: Transparent to opaque; crystalline: colorless, green, yellow and pink; massive: white, orange, pink, brown.
Hardness: 5 – 5.5
Cleavage: None; Fracture: brittle, uneven to conchoidal.
Specific gravity: 2.9 – 3.0
Refractive index: 1.625 – 1.699; Biaxial negative; 0.044
Luster: Vitreous.
Dispersion: Low
Dichroism: -
Occurrence: Igneous rock; Australia, USA, UK.
Notes
Collector’s stone; may fluoresce blue and sometimes pink or yellow; blue in short wave; usually faceted.
Crystal system: Monoclinic; short prismatic crystals of varied habit; polycrystalline; massive.
Color: Transparent to opaque; crystalline: colorless, green, yellow and pink; massive: white, orange, pink, brown.
Hardness: 5 – 5.5
Cleavage: None; Fracture: brittle, uneven to conchoidal.
Specific gravity: 2.9 – 3.0
Refractive index: 1.625 – 1.699; Biaxial negative; 0.044
Luster: Vitreous.
Dispersion: Low
Dichroism: -
Occurrence: Igneous rock; Australia, USA, UK.
Notes
Collector’s stone; may fluoresce blue and sometimes pink or yellow; blue in short wave; usually faceted.
Friday, July 13, 2007
Fortified Wine vs Heat Treated Corundum
(via Wikipedia) A fortified wine is a wine to which additional alcohol has been added, the most common additive being brandy (a spirit distilled from wine).
The original reason for fortification was to preserve wines, as the higher alcohol level and additional sweetness help to preserve the wine (when supplemental alcohol is added before fermentation finishes, it kills the yeast and leaves residual sugar). Even though other preservation methods exist, the fortification process survives, as consumers have developed tastes for wines preserved this way.
Common fortified wines include:
Sherry
Port
Marsala
Madeira
Muscat de Beaumes-de-Venise and other vins doux naturels
Fortified wines must be distinguished from spirits made from wine. While both have increased alcohol content, spirits are the result of a process of distillation, while fortified wines have spirits added to them. Fortified wines generally have an alcohol content between that of wines and spirits.
Fortified wines are legally called dessert wines in the U.S. but are called liqueur wines in Europe. In UK legislation they are called fortified wines except where the EU insists on the use of "liqueur wine".
A friend of mine who works in the gem and jewelry + wine industry had an interesting point: why not describe (old) heat treated rubies and sapphires as fortified rubies and sapphires. I had never thought about it. Not a bad idea. Then I thought about the consequences. The industry is contaminated with radioactive egomaniacs + endlessly complicated characters. Who has the guts to communicate with them? If the concept were put forward for discussion I wouldn't be surprised if there were shooting contest (s) between the wine industry, gem industry, the lab experts + the dysfunctional trade associations, but you may never know. Watch out for fortified + advanced fortified rubies and sapphires!
The original reason for fortification was to preserve wines, as the higher alcohol level and additional sweetness help to preserve the wine (when supplemental alcohol is added before fermentation finishes, it kills the yeast and leaves residual sugar). Even though other preservation methods exist, the fortification process survives, as consumers have developed tastes for wines preserved this way.
Common fortified wines include:
Sherry
Port
Marsala
Madeira
Muscat de Beaumes-de-Venise and other vins doux naturels
Fortified wines must be distinguished from spirits made from wine. While both have increased alcohol content, spirits are the result of a process of distillation, while fortified wines have spirits added to them. Fortified wines generally have an alcohol content between that of wines and spirits.
Fortified wines are legally called dessert wines in the U.S. but are called liqueur wines in Europe. In UK legislation they are called fortified wines except where the EU insists on the use of "liqueur wine".
A friend of mine who works in the gem and jewelry + wine industry had an interesting point: why not describe (old) heat treated rubies and sapphires as fortified rubies and sapphires. I had never thought about it. Not a bad idea. Then I thought about the consequences. The industry is contaminated with radioactive egomaniacs + endlessly complicated characters. Who has the guts to communicate with them? If the concept were put forward for discussion I wouldn't be surprised if there were shooting contest (s) between the wine industry, gem industry, the lab experts + the dysfunctional trade associations, but you may never know. Watch out for fortified + advanced fortified rubies and sapphires!
In Your Face
Pernilla Holmes writes about the concept of portraiture + personal identity + issues of politics, social inequity + our obsession with celebrity + other viewpoints @ http://artnews.com/issues/article.asp?art_id=2292
Think of the gem and jewelry: the unique characters and their perceptions + our obsession with celebrity + the swarm theory + the concept of jewelerture........
Think of the gem and jewelry: the unique characters and their perceptions + our obsession with celebrity + the swarm theory + the concept of jewelerture........
The Golden Years Of The Baby Boomers
Chaim Even-Zohar writes about the future of baby boomers in the U.S + GAO (General Accounting Office) analysis of national survey + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp?TextSearch=&KeyMatch=0&id=26072
China Close To Becoming Third Largest Economy
(via Economic Times) China's sizzling economy grew even faster in 2006 than previously reported, bringing it closer to overtaking Germany as the world's third-biggest, and its export-fueled foreign reserves have risen to a new high of $1.33 trillion, according to new government data.
The figures released Wednesday reflect China's stunning economic success but could fuel fears of overheating and prompt Beijing to boost interest rates or tighten regulatory controls to cool the boom. The National Bureau of Statistics raised its estimate of China's 2006 growth rate from 10.7 per cent to 11.1 per cent. It nudged up its estimate of total output to 21.1 trillion yuan ($2.705 trillion; euro 2.048 trillion), bringing China closer to overtaking Germany as the world's No. 3 economy after the United States and Japan.
The statistics agency routinely issues such revisions to economic growth rates. But the latest report could receive special attention from Chinese leaders, who are trying to rein in a boom that they worry could ignite a financial crisis.
Chinese leaders want to maintain fast growth to reduce poverty but are trying to slow investment in auto manufacturing, real estate and other areas where supply outstrips demand. They worry that runaway spending could ignite inflation or leave banks and borrowers with dangerously high debt levels.
The central bank's research bureau said last month the economy was expected to expand by 10.8 per cent this year. That was in line with projections by the World Bank and other economists, and would be China's fifth straight year of growth in excess of 10 per cent. China's trade surplus soared to a new monthly high of $26.9 billion (euro 19.8 billion) in June, the government reported Tuesday. The flood of export revenues has forced the central bank to drain billions of dollars a month from the economy through bond sales to reduce pressure for prices to rise, piling up the money in US Treasury’s and other foreign securities and helping to finance Washington's budget deficit.
The reserves, already the world's largest, rose to US$1.33 trillion (euro 965 billion) at the end of June, a 41.6 per cent increase over the same time last year, the official Xinhua News Agency said, citing the central bank. The reserves soared by $266.3 billion (euro 193 billion) in the first six months of this year, more than in all of 2006, the bank said. Beijing is creating a company to make more profitable use of the reserves through commercial investments abroad. Plans call for the company to receive an initial injection of $200 billion (euro 160 billion) in government money.
The figures released Wednesday reflect China's stunning economic success but could fuel fears of overheating and prompt Beijing to boost interest rates or tighten regulatory controls to cool the boom. The National Bureau of Statistics raised its estimate of China's 2006 growth rate from 10.7 per cent to 11.1 per cent. It nudged up its estimate of total output to 21.1 trillion yuan ($2.705 trillion; euro 2.048 trillion), bringing China closer to overtaking Germany as the world's No. 3 economy after the United States and Japan.
The statistics agency routinely issues such revisions to economic growth rates. But the latest report could receive special attention from Chinese leaders, who are trying to rein in a boom that they worry could ignite a financial crisis.
Chinese leaders want to maintain fast growth to reduce poverty but are trying to slow investment in auto manufacturing, real estate and other areas where supply outstrips demand. They worry that runaway spending could ignite inflation or leave banks and borrowers with dangerously high debt levels.
The central bank's research bureau said last month the economy was expected to expand by 10.8 per cent this year. That was in line with projections by the World Bank and other economists, and would be China's fifth straight year of growth in excess of 10 per cent. China's trade surplus soared to a new monthly high of $26.9 billion (euro 19.8 billion) in June, the government reported Tuesday. The flood of export revenues has forced the central bank to drain billions of dollars a month from the economy through bond sales to reduce pressure for prices to rise, piling up the money in US Treasury’s and other foreign securities and helping to finance Washington's budget deficit.
The reserves, already the world's largest, rose to US$1.33 trillion (euro 965 billion) at the end of June, a 41.6 per cent increase over the same time last year, the official Xinhua News Agency said, citing the central bank. The reserves soared by $266.3 billion (euro 193 billion) in the first six months of this year, more than in all of 2006, the bank said. Beijing is creating a company to make more profitable use of the reserves through commercial investments abroad. Plans call for the company to receive an initial injection of $200 billion (euro 160 billion) in government money.
Toxic Trinkets
(via Harvard's World Health News) An investigation by Florida's Tampa Tribune finds unsafe amounts of lead in inexpensive jewelry marketed to children.
"They're an irresistible buy: cheap children's jewelry and toy trinkets, lining the shelves of some of the nation's best-known retailers. And though consumers snap up these adorable items by the millions, retailers love them even more. They cost little to make overseas and can be highly profitable. But such trinkets are exposing America's children to potentially lethal levels of lead, a cheap bonding agent. The Tampa Tribune conducted an investigation of stores and federal regulations aimed at protecting consumers from such hazardous products. It found: One in three children's trinkets bought randomly in Bay area stores last month contained a level of lead considered a serious health risk to children younger than 6. Two pieces were purchased after in-house or national recalls of the toxic products had been issued, but items remained on local store shelves. Health officials, government regulators and retailers say there's no foolproof system to keep lead-tainted products out of stores, given inconsistent and lax quality controls at overseas factories. About 9 million pieces of children's jewelry have been recalled since 2006, but an understaffed and underfunded U.S. consumer regulatory agency has failed to fine a U.S. retailer or distributor for selling jewelry containing toxic levels. Blame the flood of potential danger on an expanding global marketplace."
"They're an irresistible buy: cheap children's jewelry and toy trinkets, lining the shelves of some of the nation's best-known retailers. And though consumers snap up these adorable items by the millions, retailers love them even more. They cost little to make overseas and can be highly profitable. But such trinkets are exposing America's children to potentially lethal levels of lead, a cheap bonding agent. The Tampa Tribune conducted an investigation of stores and federal regulations aimed at protecting consumers from such hazardous products. It found: One in three children's trinkets bought randomly in Bay area stores last month contained a level of lead considered a serious health risk to children younger than 6. Two pieces were purchased after in-house or national recalls of the toxic products had been issued, but items remained on local store shelves. Health officials, government regulators and retailers say there's no foolproof system to keep lead-tainted products out of stores, given inconsistent and lax quality controls at overseas factories. About 9 million pieces of children's jewelry have been recalled since 2006, but an understaffed and underfunded U.S. consumer regulatory agency has failed to fine a U.S. retailer or distributor for selling jewelry containing toxic levels. Blame the flood of potential danger on an expanding global marketplace."
The Pleasures Of Discovery
2007: A real treat from a gemological genius. Good tips for students of gemology, lab gemologists, gem dealers, jewelers and those who love colored stones.
(via The Journal of Gemmology, Vol.XIV, No.3, July 1974) B W Anderson writes:
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
In the talk I gave in January I described our early struggles in the Precious Stone Laboratory from 1925 onwards, first in learning our main job of pearl testing and later in improving and extending the techniques for testing gemstones of all kinds. Tonight, in continuing the inside story of the Laboratory I am proposing to stick pretty closely to one main theme rather than risk getting lost in recalling a host of little incidents: the theme being the story of discoveries of new gem varieties and new gem minerals in which we were lucky enough to be involved to a major or minor extent.
At present time there are some 2500 separate mineral species known to science. Each year a number of new names are added, but most of them are not only very rare but quite insignificant in form. One sometimes feels rather sorry for some worthy scientist whose name is given by its discoverer as compliment to some very indifferent mineral! The small importance of most of these in indicated by the fact that in a standard textbook such as the 1971 edition of Dana’s Manual of Mineralogy only some 200 species were considered worthy of description.
But the discovery of a new gem mineral is a rare event, for it implies that the specimens found are at least large enough to be cut as stones suitable for jewelry, and usually that they are transparent and pleasingly colored. From the trade point of view the recovery of new varieties of an already known mineral may be much more important. One has only to think of demantoid (1878), kunzite (1902), and tanzanite (1967) as instances of this.
Gahnospinel
Our first investigation into stones which had not previously been described concerned certain blue spinels from Ceylon which had a normal appearance but which were found to have a refractive index, and particularly a density, which was far higher than any quoted in the literature. C J Payne and I had already noted several such anomalous stones, but the real challenge came in 1935 when T W Oliver, who was then a gemology student at Chelsea Polytechnic, showed me a blue spinel which puzzled him in having a refractive index of over 1.74 instead of customary 1.715 or 1.72 of a spinel with so pale a lavender blue. In the laboratory we found the actual figures to be 1.7432 for the refractive index (using the minimum deviation method), and the density to be 3.947, which was even more startling.
The hunt was now on: we set to work in earnest to search for comparable stones, working through parcels of Ceylon stones borrowed from the rich stock of E Hahn & Sons, who were in those happy days established in 26, Hatton Garden. We also segregated by means of Clerici solution high density blue spinels from samples of the Ceylon gem gravels. The rarity of these anomalous stones is indicated by the fact that of over 300 spinels examined, only four had densities above 3.85.
Eventually we had in our hands a graduated range of blue spinels ranging from No.1 specimen, which was a pebble polished as a prism by Mathews Lapidaries, which gave us the measured figures of 1.7469 for refractive index and 3.981 for density, down to No.22, which had the normal values of 1.7153 and 3.584 respectively.
We realized that the replacing element causing these enhanced figures had to be one known to form a ‘spinel’ on its own and one which would have no influence on the color. Our guess that this element was zinc soon proved to be correct. We prepared a graph on which we plotted the density and refractive index of pure magnesium spinel and the corresponding figures (4.625 and 1.805) for a man-made zinc spinel, known in nature as the mineral gahnite. The zinc-rich spinels of our newly discovered series found to fit satisfactorily along the line between the two points and were well away from the line leading from the plot for magnesium spinel to that for the iron spinel, hercynite. Our ‘gahnospinels’, as we christened them, varied in color from pale to dark blue, according to their content of ferrous iron, but this had very little influence on their properties. Any considerable influx of iron causes spinel to become black and opaque and fit only for mourning jewelry. Ceylonite and pleonaste are variety names which have been used for such stones, typical values for which are 3.8 for density and 1.78 for refractive index.
We also used a small grating spectrograph made for us by Bellingham and Stanley to record the emission spectrum of small samples of stones selected from our series, fusing them in a purified carbon arc for the purpose. The spectra not only showed the expected increase in the strength of the zinc emission lines in the higher density samples, but also revealed the unexpected fact that all blue spinels from Ceylon contain at least a trace of zinc.
Dr Max Hey, the highly skilled analyst in the Mineral Department of the Natural History Museum, kindly carried out a quantitative analysis of one our ‘top’ stones and found it to contain 18.21% zinc oxide, 16.78% magnesium oxide, and 1.93% ferrous oxide—to which last the color and absorption spectrum were due. We then had enough data to justify a paper on these stones, which was published in the Mineralogical Magazine—this being the Journal of the Mineralogical Society, which is the accepted vehicle for contributions to mineralogy in this country.
This whole investigation was ideal for our first serious incursion into mineralogy. In those far-off days specimens for our purpose were readily and cheaply obtainable (Ceylon, it may be remembered, was still under the British rule); we had recently acquired a Beck table spectrometer, which enabled us, with suitably cut stones, to measure refractive indices and dispersions to four decimal places, and we were able to make accurate density determinations even on small specimens by suspension in Clerici solution followed by measurement of the R.I of the solution to our places of decimals in a hollow prism and working from a graph we had prepared showing the connexion of the density and R.I of this solution. It also gave us practice in an essential part of all research work—the art of ‘consulting the literature’ to ensure that our findings had not been already written by other workers.
A brief word on this last process may be of help to beginners in this fascinating business called research. Looking round the shelves laden with scientific journals in a big science library, such as the one in Southampton Buildings off Chancery Lane, which was formerly the Patent Office Library and is now the Science Library of the British Museum (proximity to which was not the least of our blessings), one might despair of making a thorough search. But it is not so difficult as it seems. For the past few decades at least, Mineral Abstracts have existed and a rapid search through the indexes of their more recent volumes under ‘spinel’, say, will lead you to papers on the subject that interests you. Consulting the latest of these will provide you with all the necessary references up to that time: the author will have done that work for you. A knowledge of German may be helpful, but copying facilities are provided by the library, and in ten minutes you can be provided with a photocopy which you can brood over at your leisure.
Before leaving the subject of gahnospinel I might mention that the highest figures yet encountered were in blue spinel sent for a routine test in 1964. This had density 4.06 and refractive index 1.7542. It is hardly likely that even so extreme a case might be confused with sapphire, but it is not uncommon for stones containing only a small proportion of zinc to have refractive indices around the 1.728 mark—a value associated in the mind with synthetic spinel.
The Pleasure Of Discovery (continued)
(via The Journal of Gemmology, Vol.XIV, No.3, July 1974) B W Anderson writes:
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
In the talk I gave in January I described our early struggles in the Precious Stone Laboratory from 1925 onwards, first in learning our main job of pearl testing and later in improving and extending the techniques for testing gemstones of all kinds. Tonight, in continuing the inside story of the Laboratory I am proposing to stick pretty closely to one main theme rather than risk getting lost in recalling a host of little incidents: the theme being the story of discoveries of new gem varieties and new gem minerals in which we were lucky enough to be involved to a major or minor extent.
At present time there are some 2500 separate mineral species known to science. Each year a number of new names are added, but most of them are not only very rare but quite insignificant in form. One sometimes feels rather sorry for some worthy scientist whose name is given by its discoverer as compliment to some very indifferent mineral! The small importance of most of these in indicated by the fact that in a standard textbook such as the 1971 edition of Dana’s Manual of Mineralogy only some 200 species were considered worthy of description.
But the discovery of a new gem mineral is a rare event, for it implies that the specimens found are at least large enough to be cut as stones suitable for jewelry, and usually that they are transparent and pleasingly colored. From the trade point of view the recovery of new varieties of an already known mineral may be much more important. One has only to think of demantoid (1878), kunzite (1902), and tanzanite (1967) as instances of this.
Gahnospinel
Our first investigation into stones which had not previously been described concerned certain blue spinels from Ceylon which had a normal appearance but which were found to have a refractive index, and particularly a density, which was far higher than any quoted in the literature. C J Payne and I had already noted several such anomalous stones, but the real challenge came in 1935 when T W Oliver, who was then a gemology student at Chelsea Polytechnic, showed me a blue spinel which puzzled him in having a refractive index of over 1.74 instead of customary 1.715 or 1.72 of a spinel with so pale a lavender blue. In the laboratory we found the actual figures to be 1.7432 for the refractive index (using the minimum deviation method), and the density to be 3.947, which was even more startling.
The hunt was now on: we set to work in earnest to search for comparable stones, working through parcels of Ceylon stones borrowed from the rich stock of E Hahn & Sons, who were in those happy days established in 26, Hatton Garden. We also segregated by means of Clerici solution high density blue spinels from samples of the Ceylon gem gravels. The rarity of these anomalous stones is indicated by the fact that of over 300 spinels examined, only four had densities above 3.85.
Eventually we had in our hands a graduated range of blue spinels ranging from No.1 specimen, which was a pebble polished as a prism by Mathews Lapidaries, which gave us the measured figures of 1.7469 for refractive index and 3.981 for density, down to No.22, which had the normal values of 1.7153 and 3.584 respectively.
We realized that the replacing element causing these enhanced figures had to be one known to form a ‘spinel’ on its own and one which would have no influence on the color. Our guess that this element was zinc soon proved to be correct. We prepared a graph on which we plotted the density and refractive index of pure magnesium spinel and the corresponding figures (4.625 and 1.805) for a man-made zinc spinel, known in nature as the mineral gahnite. The zinc-rich spinels of our newly discovered series found to fit satisfactorily along the line between the two points and were well away from the line leading from the plot for magnesium spinel to that for the iron spinel, hercynite. Our ‘gahnospinels’, as we christened them, varied in color from pale to dark blue, according to their content of ferrous iron, but this had very little influence on their properties. Any considerable influx of iron causes spinel to become black and opaque and fit only for mourning jewelry. Ceylonite and pleonaste are variety names which have been used for such stones, typical values for which are 3.8 for density and 1.78 for refractive index.
We also used a small grating spectrograph made for us by Bellingham and Stanley to record the emission spectrum of small samples of stones selected from our series, fusing them in a purified carbon arc for the purpose. The spectra not only showed the expected increase in the strength of the zinc emission lines in the higher density samples, but also revealed the unexpected fact that all blue spinels from Ceylon contain at least a trace of zinc.
Dr Max Hey, the highly skilled analyst in the Mineral Department of the Natural History Museum, kindly carried out a quantitative analysis of one our ‘top’ stones and found it to contain 18.21% zinc oxide, 16.78% magnesium oxide, and 1.93% ferrous oxide—to which last the color and absorption spectrum were due. We then had enough data to justify a paper on these stones, which was published in the Mineralogical Magazine—this being the Journal of the Mineralogical Society, which is the accepted vehicle for contributions to mineralogy in this country.
This whole investigation was ideal for our first serious incursion into mineralogy. In those far-off days specimens for our purpose were readily and cheaply obtainable (Ceylon, it may be remembered, was still under the British rule); we had recently acquired a Beck table spectrometer, which enabled us, with suitably cut stones, to measure refractive indices and dispersions to four decimal places, and we were able to make accurate density determinations even on small specimens by suspension in Clerici solution followed by measurement of the R.I of the solution to our places of decimals in a hollow prism and working from a graph we had prepared showing the connexion of the density and R.I of this solution. It also gave us practice in an essential part of all research work—the art of ‘consulting the literature’ to ensure that our findings had not been already written by other workers.
A brief word on this last process may be of help to beginners in this fascinating business called research. Looking round the shelves laden with scientific journals in a big science library, such as the one in Southampton Buildings off Chancery Lane, which was formerly the Patent Office Library and is now the Science Library of the British Museum (proximity to which was not the least of our blessings), one might despair of making a thorough search. But it is not so difficult as it seems. For the past few decades at least, Mineral Abstracts have existed and a rapid search through the indexes of their more recent volumes under ‘spinel’, say, will lead you to papers on the subject that interests you. Consulting the latest of these will provide you with all the necessary references up to that time: the author will have done that work for you. A knowledge of German may be helpful, but copying facilities are provided by the library, and in ten minutes you can be provided with a photocopy which you can brood over at your leisure.
Before leaving the subject of gahnospinel I might mention that the highest figures yet encountered were in blue spinel sent for a routine test in 1964. This had density 4.06 and refractive index 1.7542. It is hardly likely that even so extreme a case might be confused with sapphire, but it is not uncommon for stones containing only a small proportion of zinc to have refractive indices around the 1.728 mark—a value associated in the mind with synthetic spinel.
The Pleasure Of Discovery (continued)
Danburite
Chemistry: Calcium boro-silicate
Crystal system: Orthorhombic; striated prisms of diamond-shaped cross section, terminated by domes; distinctive chisel-shape appearance; habits similar to topaz.
Color: Transparent; yellow and colorless; rarely pink.
Hardness: 7
Cleavage: None; Fracture: sub-conchoidal.
Specific gravity: 3.0
Refractive index: 1.63 – 1.64; Biaxial positive/negative; 0.006
Luster: Vitreous.
Dispersion: Low
Dichroism: -
Occurrence: Burma, Madagascar, Mexico, Australia.
Notes
Collector’s stone; distinguished from topaz (S.G = 3.53) by lower S.G; Apatite (D.R: 0.003) by higher D.R and Tourmaline (D.R: 0.018) by lower D.R; may show rare earth spectrum; usually faceted.
Crystal system: Orthorhombic; striated prisms of diamond-shaped cross section, terminated by domes; distinctive chisel-shape appearance; habits similar to topaz.
Color: Transparent; yellow and colorless; rarely pink.
Hardness: 7
Cleavage: None; Fracture: sub-conchoidal.
Specific gravity: 3.0
Refractive index: 1.63 – 1.64; Biaxial positive/negative; 0.006
Luster: Vitreous.
Dispersion: Low
Dichroism: -
Occurrence: Burma, Madagascar, Mexico, Australia.
Notes
Collector’s stone; distinguished from topaz (S.G = 3.53) by lower S.G; Apatite (D.R: 0.003) by higher D.R and Tourmaline (D.R: 0.018) by lower D.R; may show rare earth spectrum; usually faceted.
Thursday, July 12, 2007
The Culture Of The GIA Synthetic Certificate Debate
Chaim Even-Zohar writes about the issues discussed at the GIA Symposium in San Diego + consumer confidence issues + FTC vs. industry governing bodies + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp?TextSearch=&KeyMatch=0&id=26152
SA's New Diamond Regulator Takes Shape
Polished Prices writes:
The South African government moved ahead this week with several key appointments to its state diamond regulatory body.
Among the appointments for the new regulator - in charge of licencing, the Kimberley Process and beneficiation - is Louis Selekane, current CEO of the South African Diamond Board, who will become chief executive.
Martin Mononela, previously chief director at the Department of Minerals and Energy, will act as general manager. According to Mononela, the boards of the State Diamond Trader as well as the regulator – each comprising of 16 civil and industry representatives – have already been appointed.
Based on the new South African Diamond legislation, 10% by value of the country’s diamond production must be made available to the State Diamond Trader. The government is currently in the process of appointing a State Trader, whose activities will be overseen but its own independent board of directors.
Licence holders applying for goods from the State Diamond Trader are required to polish and cut 80% of their supplies in South Africa. The remaining 20% is exempted from export duty, said Mononela.
“After personnel have been put in place at the trading body, the trading will begin," said Mononela, adding this could be as early as August 2007. “In terms of the law, the negotiations have been finalised with the producers,” he said.
The President is expected to promulgate the new legislation no later than August 2007.
More info @ http://www.polishedprices.com/article.shtml?ID=1000004502
The South African government moved ahead this week with several key appointments to its state diamond regulatory body.
Among the appointments for the new regulator - in charge of licencing, the Kimberley Process and beneficiation - is Louis Selekane, current CEO of the South African Diamond Board, who will become chief executive.
Martin Mononela, previously chief director at the Department of Minerals and Energy, will act as general manager. According to Mononela, the boards of the State Diamond Trader as well as the regulator – each comprising of 16 civil and industry representatives – have already been appointed.
Based on the new South African Diamond legislation, 10% by value of the country’s diamond production must be made available to the State Diamond Trader. The government is currently in the process of appointing a State Trader, whose activities will be overseen but its own independent board of directors.
Licence holders applying for goods from the State Diamond Trader are required to polish and cut 80% of their supplies in South Africa. The remaining 20% is exempted from export duty, said Mononela.
“After personnel have been put in place at the trading body, the trading will begin," said Mononela, adding this could be as early as August 2007. “In terms of the law, the negotiations have been finalised with the producers,” he said.
The President is expected to promulgate the new legislation no later than August 2007.
More info @ http://www.polishedprices.com/article.shtml?ID=1000004502
A Diamond District Far From 47th Street
Hilary Larson writes about Brugges and Antwerp + its international status as the center for diamonds and fashion + other viewpoints @ http://www.thejewishweek.com/news/newscontent.php3?artid=14252
Precious Stones Of The Future From The Laboratory
An insider (s) view + tips for students studying synthetic gemstone identification course (s).
(via The Journal of Gemmology, Vol.XVI, No.7, July 1979)
A report on M. Pierre Gilson’s talk
On the 11th October, 1978, a talk was given to members of the Association by M Pierre Gilson on ‘Precious Stones of the Future from the Laboratory’ in the Geological Museum Cinema Theatre, South Kensington. The theatre was full when the proceedings were opened and the speaker was introduced by the vice-chairman, Dr David Callaghan, FGA, who said M Gilson produced the very best that man could produce and was able to do in a relatively short time things which Nature took very much longer to achieve; his talent and the vast range of materials that he was producing were quite fantastic.
M Gilson’s talk then took the form of a running commentary no the hundred or so slides which he showed during the evening and he left few people in doubt about the progress made in the last fifty or sixty years. He reminded the audience that Verneuil was the first to make synthetic ruby and sapphire at the beginning of the century: with his relatively simple method he was able to produce a boule in one of several colors in a matter of three hours or so, and his synthetic corundum was soon used to make the jewels in watches.
In contrast, M Gilson’s company takes as long as nine months to grow synthetic emeralds. They start with a seed—synthetic material of the highest quality—and grow it as a non-stop process for nine months. A continuous supply of electricity is essential, because it is important to allow crystallization to take place at a constant temperature if good crystals are to be grown. Accordingly arrangements have been made to ensure that the company is guaranteed a supply of electricity privately in case there should be a failure in the public supply due to breakdown or perhaps a strike.
But it is not just a matter of having the right equipment and know how: experimentation also is necessary. Before success in making synthetic turquoise was achieved, thirty different phosphates had to be crystallized.
The equipment now used in the Gilson laboratories is very sophisticated and quite advanced. In order to study the size and formation of the tiny ‘beads’ which make up such gemstones as emeralds an electron microscope is used. A spectrophotometer is another essential piece of equipment, because it is important to be able to control absorption to within one part per million.
With synthetic emeralds M Gilson has found it beneficial to cut at a specific angle in relation to the seed crystal on which the new material has been grown. He used slides to explain that the main difference between synthetic and natural emerald lies in the nature of the inclusions. In the synthetic material the ‘veil’ is twisted, whereas in the natural stone it is straight. He added that Nature produced only one good emerald for every million crystals formed: in the laboratory it was essential to have a very much higher success rate. Emerald production in the Gilson laboratory takes precisely nine months, since, if you wait any longer, crystallization may have stopped. A simple—but impractical! –test to distinguish between natural and synthetic emerald was mentioned: if you heat it to one thousand degrees and it turns white when it cools, you know it is natural. He added that the hardness of emerald was affected by the extent of inclusions in a given stone.
Opal was next discussed. Opal is pure silica: it acts like a prism and the colors which can be seen are pure spectral colors. Gilson synthetic opals contain more pure colors than natural material because they contain more pure constituents. Laboratory production of opal calls for a very high temperature: natural opal is no longer being created because temperatures are not high enough. Even in the laboratory it is impossible to produce two identical opals. Production starts with the production of millions of tiny beads, each about 0.3 microns in diameter, and these eventually form the finished material. M Gilson’s most recent improvements involve the removal of all traces of water from synthetic opals, and this gets rid of cracks and helps to avoid some of the hazards associated with the natural material. With natural opals, it is interesting to note that material found at depth of more than six meters is often noticeably better than stones found near the surface.
Natural turquoise contains iron, and in some cases customers are disappointed when the iron turns green after a year or two. ‘Our own stones are pure turquoise, so this problem doesn’t arise’—but a process has now been developed so that iron can be introduced to the surface of synthetic turquoise.
With lapis, although pyrites (its inclusions) can be synthesized, M Gilson uses natural pyrites. ‘Each day nine hundred tons of natural pyrites are mined: I cannot compete with that!’ He is now successfully synthesizing coral and used calcite which is now being mined in France.
In answer to a question whether he could suggest any methods of testing stones to tell the difference between real and synthetic specimens, he said: ‘We work on developing new scientific products, but when it comes to identification you are the experts.’ Asked whether it was his intention to produce stones so similar to the natural product that they could not be detected, he replied: ‘We are not competing with Nature but merely trying to improve on it by producing more pure stones—more beautiful ones for the jeweler to work with.’
Mr Alec Farn asked if M Gilson had produced any emeralds without chromium but with the addition of vanadium, and M Gilson replied that he had not—and even if it was done, could the result be described as emerald?’ ‘If people want chromium in emerald, then why shouldn’t we give it to them?’
Offering a tip for improving opals, M Gilson said that if soaked over night in ethyl alcohol all moisture in the stone would be driven out and the color improved—but it was essential not to do this if the stone was a triplet! And in reply to an enquiry whether he had carried out any experiment on the jadeite family, he smiled and said: ‘Yes, we are working on this problem.’
When asked how long he had been trying to make synthetic stones before he had his first success, he said he took fifteen years to succeed with emerald, ten years with opal, and eight years with turquoise: and because of slow reactions and the length of time it took to grow a single crystal before it was known whether or not the experiment was a success, research was becoming more difficult and expensive. Some members of the audience were surprised when M Gilson mentioned that his main business was not the production of synthetic gemstones but the manufacture of about nine tons of ceramics each month for industrial use.
(via The Journal of Gemmology, Vol.XVI, No.7, July 1979)
A report on M. Pierre Gilson’s talk
On the 11th October, 1978, a talk was given to members of the Association by M Pierre Gilson on ‘Precious Stones of the Future from the Laboratory’ in the Geological Museum Cinema Theatre, South Kensington. The theatre was full when the proceedings were opened and the speaker was introduced by the vice-chairman, Dr David Callaghan, FGA, who said M Gilson produced the very best that man could produce and was able to do in a relatively short time things which Nature took very much longer to achieve; his talent and the vast range of materials that he was producing were quite fantastic.
M Gilson’s talk then took the form of a running commentary no the hundred or so slides which he showed during the evening and he left few people in doubt about the progress made in the last fifty or sixty years. He reminded the audience that Verneuil was the first to make synthetic ruby and sapphire at the beginning of the century: with his relatively simple method he was able to produce a boule in one of several colors in a matter of three hours or so, and his synthetic corundum was soon used to make the jewels in watches.
In contrast, M Gilson’s company takes as long as nine months to grow synthetic emeralds. They start with a seed—synthetic material of the highest quality—and grow it as a non-stop process for nine months. A continuous supply of electricity is essential, because it is important to allow crystallization to take place at a constant temperature if good crystals are to be grown. Accordingly arrangements have been made to ensure that the company is guaranteed a supply of electricity privately in case there should be a failure in the public supply due to breakdown or perhaps a strike.
But it is not just a matter of having the right equipment and know how: experimentation also is necessary. Before success in making synthetic turquoise was achieved, thirty different phosphates had to be crystallized.
The equipment now used in the Gilson laboratories is very sophisticated and quite advanced. In order to study the size and formation of the tiny ‘beads’ which make up such gemstones as emeralds an electron microscope is used. A spectrophotometer is another essential piece of equipment, because it is important to be able to control absorption to within one part per million.
With synthetic emeralds M Gilson has found it beneficial to cut at a specific angle in relation to the seed crystal on which the new material has been grown. He used slides to explain that the main difference between synthetic and natural emerald lies in the nature of the inclusions. In the synthetic material the ‘veil’ is twisted, whereas in the natural stone it is straight. He added that Nature produced only one good emerald for every million crystals formed: in the laboratory it was essential to have a very much higher success rate. Emerald production in the Gilson laboratory takes precisely nine months, since, if you wait any longer, crystallization may have stopped. A simple—but impractical! –test to distinguish between natural and synthetic emerald was mentioned: if you heat it to one thousand degrees and it turns white when it cools, you know it is natural. He added that the hardness of emerald was affected by the extent of inclusions in a given stone.
Opal was next discussed. Opal is pure silica: it acts like a prism and the colors which can be seen are pure spectral colors. Gilson synthetic opals contain more pure colors than natural material because they contain more pure constituents. Laboratory production of opal calls for a very high temperature: natural opal is no longer being created because temperatures are not high enough. Even in the laboratory it is impossible to produce two identical opals. Production starts with the production of millions of tiny beads, each about 0.3 microns in diameter, and these eventually form the finished material. M Gilson’s most recent improvements involve the removal of all traces of water from synthetic opals, and this gets rid of cracks and helps to avoid some of the hazards associated with the natural material. With natural opals, it is interesting to note that material found at depth of more than six meters is often noticeably better than stones found near the surface.
Natural turquoise contains iron, and in some cases customers are disappointed when the iron turns green after a year or two. ‘Our own stones are pure turquoise, so this problem doesn’t arise’—but a process has now been developed so that iron can be introduced to the surface of synthetic turquoise.
With lapis, although pyrites (its inclusions) can be synthesized, M Gilson uses natural pyrites. ‘Each day nine hundred tons of natural pyrites are mined: I cannot compete with that!’ He is now successfully synthesizing coral and used calcite which is now being mined in France.
In answer to a question whether he could suggest any methods of testing stones to tell the difference between real and synthetic specimens, he said: ‘We work on developing new scientific products, but when it comes to identification you are the experts.’ Asked whether it was his intention to produce stones so similar to the natural product that they could not be detected, he replied: ‘We are not competing with Nature but merely trying to improve on it by producing more pure stones—more beautiful ones for the jeweler to work with.’
Mr Alec Farn asked if M Gilson had produced any emeralds without chromium but with the addition of vanadium, and M Gilson replied that he had not—and even if it was done, could the result be described as emerald?’ ‘If people want chromium in emerald, then why shouldn’t we give it to them?’
Offering a tip for improving opals, M Gilson said that if soaked over night in ethyl alcohol all moisture in the stone would be driven out and the color improved—but it was essential not to do this if the stone was a triplet! And in reply to an enquiry whether he had carried out any experiment on the jadeite family, he smiled and said: ‘Yes, we are working on this problem.’
When asked how long he had been trying to make synthetic stones before he had his first success, he said he took fifteen years to succeed with emerald, ten years with opal, and eight years with turquoise: and because of slow reactions and the length of time it took to grow a single crystal before it was known whether or not the experiment was a success, research was becoming more difficult and expensive. Some members of the audience were surprised when M Gilson mentioned that his main business was not the production of synthetic gemstones but the manufacture of about nine tons of ceramics each month for industrial use.
Subscribe to:
Posts (Atom)