The Christmas Tree cut was developed about two decades ago by George Saltzman, New York. Rough triangular macle is polished with grooves depicting the branches of a pine tree. The stones are still being cut in limited quantities in Israel and Belgium.
Green or blue diamonds are desirable for this cut, the latter being a representation of a blue spruce tree. Off- color colored diamonds may be irradiated to achieve the desirable colors. Christmas tree cut is popular with Christmas tree farmers.
Friday, January 12, 2007
A Quick Look At Jewelry Hallmark
David Foard writes:
British Hallmarks are the best in the world. Who says so, the rest of the World. Although to be fair, other countries have great hallmarks too, it is just that they are NOT so often seen.
A book on World Hallmarks for Gold or Silver items is a must for any serious collector or dealer, but they can be a little intimidating and time consuming. Is that mark a Cockerel or a Tree? Could it be made in Switzerland or Germany?
Thankfully for the rest of us, a small pocket book on UK Hallmarks is more than up to the task, coupled with that very useful plastic 10X eyeglass I keep on hinting for you to buy.
It will show you that the item has been tested and stamped, to prove it is - what it says it is (9ct or 18ct etc). British Jewelry with a full UKHM (United Kingdom Hall Mark) is generally clearly stamped and readable after you clean it (check the website below for another complimentary article on 'How to Clean your Jewelry at Home').
Once you are aware of the marks, you will always feel just that little bit better when you buy that 'Could it be an Antique?' item at the local market, or from the guy in the Pub that everyone talks about but nobody knows. Buyer Beware....
*Six marks on British Jewelry.*
Yes... Six?
# 1: The Maker's Mark (Usually some initials). Not all that important for everyday items, unless you want to collect Jewelry from one maker. Silver collectors may want to buy items from say, Bateman (I should be so lucky).
# 2: The second stamp is the Assay Office mark or 'Mark of Origin'. It tells you where the item came from. The most common is the LONDON Hallmark. A Leopard's Head.
Sometimes this has a crown on the Leopard's Head (until circa 1821). Modern items do NOT have a crown on the Leopard Stamp.
The other most common Assay Office marks are from Birmingham (an Anchor). Once there were many Assay offices around Great Britain and Ireland, the Chester mark for instance. Now there are just three offices left in England, Sheffield being the last using a 'Rose' on gold Jewelry (DO NOT CONFUSE THIS WITH 'ROSE GOLD' JEWELRY) as that is a color, not a mark.
In Scotland there is Edinburgh, while in Ireland there is Dublin. Pity the poor Welsh are left out again!
# 3: The next is the Assay Quality mark and is shown as the 'Lion Passant' (which means 'looking ahead') and is a guarantee of quality. This was later changed to a 'CROWN' mark with a stamp showing the quality of Gold.... 9ct or 18ct etc.
# 4: Finally, and possibly the most important mark, was the Date letter mark. It changed each year so we can tell when the item was made.
Occasionally there is an extra mark.
# 5: An example was the Queen's Silver Jubilee in 1977.
Suffice to say if you see a Brooch with four or five marks and one of them is an Anchor with an 18 next to it and a letter 'C' next to that.... It's a safe bet it was made in Birmingham in 1927, or was that 1952, or 1902, or, or, or.....
Buyer Beware the man in the Pub.
As with most Jewelry items though, our advise has always been to buy the best QUALITY you can afford from a reputable dealer who will guarantee it.
Other than that, your plastic 10X eyeglass sure helps a lot....
David Foard has spent over 30 years in the Antique Jewelry Trade as a qualified gemologist and member of the Valuers Council.
More info @ http://www.jewellery-antiques.com
http://ezinearticles.com/?A-Quick-Look-at-Jewelry-Hallmarks&id=72739
http://EzineArticles.com/?expert=David_Foard
British Hallmarks are the best in the world. Who says so, the rest of the World. Although to be fair, other countries have great hallmarks too, it is just that they are NOT so often seen.
A book on World Hallmarks for Gold or Silver items is a must for any serious collector or dealer, but they can be a little intimidating and time consuming. Is that mark a Cockerel or a Tree? Could it be made in Switzerland or Germany?
Thankfully for the rest of us, a small pocket book on UK Hallmarks is more than up to the task, coupled with that very useful plastic 10X eyeglass I keep on hinting for you to buy.
It will show you that the item has been tested and stamped, to prove it is - what it says it is (9ct or 18ct etc). British Jewelry with a full UKHM (United Kingdom Hall Mark) is generally clearly stamped and readable after you clean it (check the website below for another complimentary article on 'How to Clean your Jewelry at Home').
Once you are aware of the marks, you will always feel just that little bit better when you buy that 'Could it be an Antique?' item at the local market, or from the guy in the Pub that everyone talks about but nobody knows. Buyer Beware....
*Six marks on British Jewelry.*
Yes... Six?
# 1: The Maker's Mark (Usually some initials). Not all that important for everyday items, unless you want to collect Jewelry from one maker. Silver collectors may want to buy items from say, Bateman (I should be so lucky).
# 2: The second stamp is the Assay Office mark or 'Mark of Origin'. It tells you where the item came from. The most common is the LONDON Hallmark. A Leopard's Head.
Sometimes this has a crown on the Leopard's Head (until circa 1821). Modern items do NOT have a crown on the Leopard Stamp.
The other most common Assay Office marks are from Birmingham (an Anchor). Once there were many Assay offices around Great Britain and Ireland, the Chester mark for instance. Now there are just three offices left in England, Sheffield being the last using a 'Rose' on gold Jewelry (DO NOT CONFUSE THIS WITH 'ROSE GOLD' JEWELRY) as that is a color, not a mark.
In Scotland there is Edinburgh, while in Ireland there is Dublin. Pity the poor Welsh are left out again!
# 3: The next is the Assay Quality mark and is shown as the 'Lion Passant' (which means 'looking ahead') and is a guarantee of quality. This was later changed to a 'CROWN' mark with a stamp showing the quality of Gold.... 9ct or 18ct etc.
# 4: Finally, and possibly the most important mark, was the Date letter mark. It changed each year so we can tell when the item was made.
Occasionally there is an extra mark.
# 5: An example was the Queen's Silver Jubilee in 1977.
Suffice to say if you see a Brooch with four or five marks and one of them is an Anchor with an 18 next to it and a letter 'C' next to that.... It's a safe bet it was made in Birmingham in 1927, or was that 1952, or 1902, or, or, or.....
Buyer Beware the man in the Pub.
As with most Jewelry items though, our advise has always been to buy the best QUALITY you can afford from a reputable dealer who will guarantee it.
Other than that, your plastic 10X eyeglass sure helps a lot....
David Foard has spent over 30 years in the Antique Jewelry Trade as a qualified gemologist and member of the Valuers Council.
More info @ http://www.jewellery-antiques.com
http://ezinearticles.com/?A-Quick-Look-at-Jewelry-Hallmarks&id=72739
http://EzineArticles.com/?expert=David_Foard
Amsterdam Sauer
Amsterdam Sauer writes:
Jules Roger Sauer, a French born from Alsace-Loraine, immigrated to Brazil, alone, in 1939, when he was just 18 years old.Although he could speak four languages, Portuguese was not among those he knew. Jules was very young and had no idea of which profession to pursue.After being introduced to some precious gems, he became immediately fascinated by them and decided to establish himself in the capital of the state of Minas Gerais, Belo Horizonte, which had the richest diversity of colored stones in the world at the time.Traveling in the vast and wild landscape of Minas Gerais, Jules first got involved in prospecting for diamonds . After a while, though, he realized the untapped future potential of the colored stones business. Armed with that knowledge, he began channeling his efforts at becoming an industry expert on colored gemstones.
With a minimal start-up capital of approximately ten thousand dollars, Jules founded his company in 1941. He named it Amsterdam Limited. The city of Amsterdam, Holland was the world’s benchmark for excellence in the cutting and trading of diamonds. Sauer also had wonderful memories and a tremendous admiration for the Dutch people.
In just a few years, Amsterdam Limited became an important Brazilian gemstone trading company, involved in mining, purchasing, cutting and wholesaling fine colored stones. The company mainly worked with aquamarines, tourmalines, imperial topazes, amethysts and citrines at the time.
Jules married Zilda in 1950 and the couple decided to move to Rio de Janeiro, the capital and the financial center of Brazil. There, the Sauer added jewelry manufacturing to the company’s list of business activities.The first retail store was inaugurated, in 1953, beside the famous Copacabana Palace Hotel. The store was initially named SAUER. Later, the company became a single entity named AMSTERDAM SAUER, as it is commonly known today.
Jules and Zilda built Amsterdam Sauer into the only 100% vertically integrated Brazilian company. From mining to retailing, Amsterdam Sauer controls every step of the jewelry production - never losing the focus on quality. Due to this precise expertise the company consistently displayed in the jewelry industry, it earned international recognition through its global clientele and various prestigious industry awards.
Amsterdam Sauer was the first South American Jeweler to be awarded, in 1966, the coveted De Beers - Diamond International Awards, with the Constellation Ring. The company holds a total of three De Beers - Diamond International Awards.
The emerald was only first discovered in Brazil in 1963. Jules Sauer was the pioneer in mining and marketing Brazilian emeralds. Again, Jules saw the great potential of this universal gemstone. He obtained the historical certification from the Gemological Institute of America for the Salininha Brazilian emeralds. Following this momentous event, the world began to recognize Brazil as a major producer of emeralds - a landmark and definitive turning point in the history of the Brazilian gemstone trade. Amsterdam Sauer evolved with these changes, becoming the most respected specialist on Brazilian and Colombian emeralds in South America.
Amsterdam Sauer is a modern company employing over 300 highly motivated associates, blending state of the art technology with traditional handcrafted techniques to meet the highest standards through its unique jewelry creations. The continued international success of the company is a direct result of the consistency of high quality products and services, unique expertise of fine gemstone jewelry and the personal dedication of its multilingual consultants for catering to a broad international clientele.
Independent from the business side, the Sauer family’s fascination for gemstones inspired the formation of its own private and rare gemstone collection over the past six decades. It is the most diversified in South America and is now available for public exhibition at the Amsterdam Sauer Museum in Rio de Janeiro. Parts of the collection may also be viewed at special displays in various Amsterdam Sauer stores.
The story and the quest of Jules Sauer and his family can also be found in the three books written by him;
Brazil Paradise of Gemstones – 1982
Emeralds Around the World – 1992
The Eras of the Diamond – 2002
Presently, Amsterdam Sauer has 25 retail stores in Brazil and representatives in larger cities around the globe. The company is managed by the second generation of the Sauer family. The Sauer third generation is already in the process of joining the group.
More info @ www.amsterdamsauer.com
Jules Roger Sauer, a French born from Alsace-Loraine, immigrated to Brazil, alone, in 1939, when he was just 18 years old.Although he could speak four languages, Portuguese was not among those he knew. Jules was very young and had no idea of which profession to pursue.After being introduced to some precious gems, he became immediately fascinated by them and decided to establish himself in the capital of the state of Minas Gerais, Belo Horizonte, which had the richest diversity of colored stones in the world at the time.Traveling in the vast and wild landscape of Minas Gerais, Jules first got involved in prospecting for diamonds . After a while, though, he realized the untapped future potential of the colored stones business. Armed with that knowledge, he began channeling his efforts at becoming an industry expert on colored gemstones.
With a minimal start-up capital of approximately ten thousand dollars, Jules founded his company in 1941. He named it Amsterdam Limited. The city of Amsterdam, Holland was the world’s benchmark for excellence in the cutting and trading of diamonds. Sauer also had wonderful memories and a tremendous admiration for the Dutch people.
In just a few years, Amsterdam Limited became an important Brazilian gemstone trading company, involved in mining, purchasing, cutting and wholesaling fine colored stones. The company mainly worked with aquamarines, tourmalines, imperial topazes, amethysts and citrines at the time.
Jules married Zilda in 1950 and the couple decided to move to Rio de Janeiro, the capital and the financial center of Brazil. There, the Sauer added jewelry manufacturing to the company’s list of business activities.The first retail store was inaugurated, in 1953, beside the famous Copacabana Palace Hotel. The store was initially named SAUER. Later, the company became a single entity named AMSTERDAM SAUER, as it is commonly known today.
Jules and Zilda built Amsterdam Sauer into the only 100% vertically integrated Brazilian company. From mining to retailing, Amsterdam Sauer controls every step of the jewelry production - never losing the focus on quality. Due to this precise expertise the company consistently displayed in the jewelry industry, it earned international recognition through its global clientele and various prestigious industry awards.
Amsterdam Sauer was the first South American Jeweler to be awarded, in 1966, the coveted De Beers - Diamond International Awards, with the Constellation Ring. The company holds a total of three De Beers - Diamond International Awards.
The emerald was only first discovered in Brazil in 1963. Jules Sauer was the pioneer in mining and marketing Brazilian emeralds. Again, Jules saw the great potential of this universal gemstone. He obtained the historical certification from the Gemological Institute of America for the Salininha Brazilian emeralds. Following this momentous event, the world began to recognize Brazil as a major producer of emeralds - a landmark and definitive turning point in the history of the Brazilian gemstone trade. Amsterdam Sauer evolved with these changes, becoming the most respected specialist on Brazilian and Colombian emeralds in South America.
Amsterdam Sauer is a modern company employing over 300 highly motivated associates, blending state of the art technology with traditional handcrafted techniques to meet the highest standards through its unique jewelry creations. The continued international success of the company is a direct result of the consistency of high quality products and services, unique expertise of fine gemstone jewelry and the personal dedication of its multilingual consultants for catering to a broad international clientele.
Independent from the business side, the Sauer family’s fascination for gemstones inspired the formation of its own private and rare gemstone collection over the past six decades. It is the most diversified in South America and is now available for public exhibition at the Amsterdam Sauer Museum in Rio de Janeiro. Parts of the collection may also be viewed at special displays in various Amsterdam Sauer stores.
The story and the quest of Jules Sauer and his family can also be found in the three books written by him;
Brazil Paradise of Gemstones – 1982
Emeralds Around the World – 1992
The Eras of the Diamond – 2002
Presently, Amsterdam Sauer has 25 retail stores in Brazil and representatives in larger cities around the globe. The company is managed by the second generation of the Sauer family. The Sauer third generation is already in the process of joining the group.
More info @ www.amsterdamsauer.com
Clinging To Failed Ideas
Charles T Munger, Vice-Chairman of Berkshire Hathaway Corporation writes:
I want to tell one more story demonstrating how awful it is to get a wrong idea from a limited repertoire and just stick to it. And this is the story of Hyman Liebowitz who came to America from the old country. In the new country, as in the old, he tried to make his way in the family trade, which was manufacturing nails. And he struggled, and finally his little nail business got to vast prosperity, and his wife said to him, "You are old, Hyman, it's time to go to Florida and turn the business over to our son."
So down he went to Florida, turning his business over to the son, but he got weekly financial reports. And he hadn't been in Florida very long before they turned sharply negative. In fact, they were terrible. So he got on an airplane and he went back to New Jersey, where the factory was. As he left the airport on the way to the factory he saw this enormous outdoor advertising sign lighting up. And there was Jesus, spread out on the cross. And under it was a big legend, "They Used Liebowitz's Nails." So he stormed into the factory and said, "You dumb son! What do you think you are doing? It took me 50 years to create this business!" "Papa," he said, "trust me. I will fix it."
So back he went to Florida, and while he was in Florida he got more reports, and the results kept getting worse. So he got on the airplane again. Left the airport, drove by the sign, looked up at this big lighted sign, and now there's a vacant cross. And, low and behold, Jesus is crumpled on the ground under the cross, and the sign said, "They Didn't Use Liebowitz's Nails."
Well, you can laugh at that. It is ridiculous but it's no more ridiculous than the way a lot of people cling to failed ideas. Keynes said, "It's not bringing in the new ideas that's so hard. It's getting rid of the old ones." And Einstein said it better, attributing his mental success to "curiosity, concentration, perserverance and self-criticism. By self-criticism he meant becoming good at destryoing your own best-loved and hardest-won ideas. If you can get really good at destryoing your own wrong ideas, that's a great gift.
I want to tell one more story demonstrating how awful it is to get a wrong idea from a limited repertoire and just stick to it. And this is the story of Hyman Liebowitz who came to America from the old country. In the new country, as in the old, he tried to make his way in the family trade, which was manufacturing nails. And he struggled, and finally his little nail business got to vast prosperity, and his wife said to him, "You are old, Hyman, it's time to go to Florida and turn the business over to our son."
So down he went to Florida, turning his business over to the son, but he got weekly financial reports. And he hadn't been in Florida very long before they turned sharply negative. In fact, they were terrible. So he got on an airplane and he went back to New Jersey, where the factory was. As he left the airport on the way to the factory he saw this enormous outdoor advertising sign lighting up. And there was Jesus, spread out on the cross. And under it was a big legend, "They Used Liebowitz's Nails." So he stormed into the factory and said, "You dumb son! What do you think you are doing? It took me 50 years to create this business!" "Papa," he said, "trust me. I will fix it."
So back he went to Florida, and while he was in Florida he got more reports, and the results kept getting worse. So he got on the airplane again. Left the airport, drove by the sign, looked up at this big lighted sign, and now there's a vacant cross. And, low and behold, Jesus is crumpled on the ground under the cross, and the sign said, "They Didn't Use Liebowitz's Nails."
Well, you can laugh at that. It is ridiculous but it's no more ridiculous than the way a lot of people cling to failed ideas. Keynes said, "It's not bringing in the new ideas that's so hard. It's getting rid of the old ones." And Einstein said it better, attributing his mental success to "curiosity, concentration, perserverance and self-criticism. By self-criticism he meant becoming good at destryoing your own best-loved and hardest-won ideas. If you can get really good at destryoing your own wrong ideas, that's a great gift.
Giant Size Top Color Clean Tsavorite Discovered in East Africa
(via) PR Web writes:
An exceptional gemstone, most likely the largest fine color clean tsavorite in the world was discovered near Arusha, Tanzania. The stone was found at the border of the original block B tanzanite mining area (Block B extension), at a depth of 160 meters. The area is locally known as Karo.
The uncut stone weighed 185 grams and was examined by Dr. H. Hanni of SSEF Swiss Gemmological Institute during a recent trip to Arusha. The stone was preformed and facetted at the Multicolour Gems office in Chantaburi and certified by Dr. A. Peretti at the GRS Gemresearch Swisslab in Bangkok. The impressive size and saturated color combined with remarkable clarity and transparency put this stone in a class of its own. According to Dr. A. Peretti's report, -- "One Magnificent Gemstone".
More info @ http://prweb.com/pingpr.php/UGlnZy1QaWdnLVByb2YtVGhpci1NYWduLVplcm8=
http://news.yahoo.com/s/prweb/20070107/bs_prweb/prweb495411
An exceptional gemstone, most likely the largest fine color clean tsavorite in the world was discovered near Arusha, Tanzania. The stone was found at the border of the original block B tanzanite mining area (Block B extension), at a depth of 160 meters. The area is locally known as Karo.
The uncut stone weighed 185 grams and was examined by Dr. H. Hanni of SSEF Swiss Gemmological Institute during a recent trip to Arusha. The stone was preformed and facetted at the Multicolour Gems office in Chantaburi and certified by Dr. A. Peretti at the GRS Gemresearch Swisslab in Bangkok. The impressive size and saturated color combined with remarkable clarity and transparency put this stone in a class of its own. According to Dr. A. Peretti's report, -- "One Magnificent Gemstone".
More info @ http://prweb.com/pingpr.php/UGlnZy1QaWdnLVByb2YtVGhpci1NYWduLVplcm8=
http://news.yahoo.com/s/prweb/20070107/bs_prweb/prweb495411
Running A Business
( via Fortune, April 11, 1988) Warren Edward Buffett, CEO, Berkshire Hathaway writes:
'Can you really explain to a fish what it's like to walk on land? One day on land is worth a thousand years of talking about it. And one day running a business has exactly the same kind of value.'
'Can you really explain to a fish what it's like to walk on land? One day on land is worth a thousand years of talking about it. And one day running a business has exactly the same kind of value.'
Thursday, January 11, 2007
How To Become A Diamond Sightholder
Rough diamonds are usually channeled through the CSO (Central Selling Organization)--a De Beers affiliate, from the mine to the cutting and polishing centers. The role of CSO has significantly changed and the system of single channel marketing has more or less become obsolete.
A sightholder may be a diamond manufacturer with large cutting facilities or rough diamond dealer, who may resell rough diamonds to small dealers, or Diamdel, a CSO affiliated rough trading company
Rough diamonds are sold ten times per year at gatherings in London known as sights. Attendance to sights is by invitation only. Buyers who attend the sights are known as sightholders. Sightholders go through a broker who acts as a mediator between the CSO and the sightholder. A 1% commission is paid by the sightholder to the broker based on the value of their sights. Most sights are approximately US$500000 to millions, in cash. The estimated time it takes for diamond to get from mine to producer is approximately 2.5 years.
The diamond pipeline is pretty much the same, but the role of the CSO has changed. It has subsequently been renamed the DTC (Diamond Trading Company).The new business strategy for DTC is to monitor the rough all the way through to retailing. The greatest value addition is between diamond manufacturing and retail sales, which has a mark up of more than 100 per cent. The DTC is now involved in diamond processing, jewelry manufacturing and marketing.
The new sightholder requirements are:
1. The sightholder must have solid financial standing and reliability.
2. The sightholder must have the ability to efficiently distribute diamonds to other dealers and manufacturers.
3. The sightholder must have the marketing ability on their own or together with retailers aimed at increasing consumer demand.
4. The sightholder must have a strong geographic market position.
5. The sightholder must endorse and comply with best practice policy (BPP).
6. The sightholder should not deal in synthetic diamonds.
7. The sightholder must have personal integrity and technical expertise with respect to particular diamonds.
A sightholder may be a diamond manufacturer with large cutting facilities or rough diamond dealer, who may resell rough diamonds to small dealers, or Diamdel, a CSO affiliated rough trading company
Rough diamonds are sold ten times per year at gatherings in London known as sights. Attendance to sights is by invitation only. Buyers who attend the sights are known as sightholders. Sightholders go through a broker who acts as a mediator between the CSO and the sightholder. A 1% commission is paid by the sightholder to the broker based on the value of their sights. Most sights are approximately US$500000 to millions, in cash. The estimated time it takes for diamond to get from mine to producer is approximately 2.5 years.
The diamond pipeline is pretty much the same, but the role of the CSO has changed. It has subsequently been renamed the DTC (Diamond Trading Company).The new business strategy for DTC is to monitor the rough all the way through to retailing. The greatest value addition is between diamond manufacturing and retail sales, which has a mark up of more than 100 per cent. The DTC is now involved in diamond processing, jewelry manufacturing and marketing.
The new sightholder requirements are:
1. The sightholder must have solid financial standing and reliability.
2. The sightholder must have the ability to efficiently distribute diamonds to other dealers and manufacturers.
3. The sightholder must have the marketing ability on their own or together with retailers aimed at increasing consumer demand.
4. The sightholder must have a strong geographic market position.
5. The sightholder must endorse and comply with best practice policy (BPP).
6. The sightholder should not deal in synthetic diamonds.
7. The sightholder must have personal integrity and technical expertise with respect to particular diamonds.
Diamond Cut: Buddha Cut
The Buddha cut, a diamond polished in the shape of a meditating Buddha, was co-designed in 1995 by a Buddhist member of the Japanese Soto Zen federation and Oliver Korn for J Korn & Partners. The name is a patent of Antwerp-based diamond manufacturer J Korn & Partners, which also holds a copyright on the shape. The Buddha cut is produced by Oliver Korn for J Korn & Partners.
The cut is perceived as a three-dimensional sculpture that fits well into jewelry. The Buddha, hand cut in Antwerp, is faceted like modern brilliant cuts with 33 crown facets, 21 pavilion facets and a culet. The girdle is also faceted. The different styles of Buddha cut diamonds have historical and regional significance. The Shakyamuni Buddha represents the historical Buddha of India. The Kwan Yin (China) or Kannon (Japan) represents the feminine form of Buddha. A third styling, the Thai representation of the Buddha is available by special order only.
Buddha diamonds are most commonly set as center stones for pendants and rings. Brooches and tiepins are also common uses. For religious reasons, they are not used as earrings.
The cut is perceived as a three-dimensional sculpture that fits well into jewelry. The Buddha, hand cut in Antwerp, is faceted like modern brilliant cuts with 33 crown facets, 21 pavilion facets and a culet. The girdle is also faceted. The different styles of Buddha cut diamonds have historical and regional significance. The Shakyamuni Buddha represents the historical Buddha of India. The Kwan Yin (China) or Kannon (Japan) represents the feminine form of Buddha. A third styling, the Thai representation of the Buddha is available by special order only.
Buddha diamonds are most commonly set as center stones for pendants and rings. Brooches and tiepins are also common uses. For religious reasons, they are not used as earrings.
Diamond Cut: Tycoon Cut
The Tycoon Cut™ was invented in 1999 by Toros Kejejian . The name Tycoon Cut is trademarked, and has been patented in both the US and internationally. Los Angles based Tycoon Jewelry is its sole distributor.
The cut is a rectangular mixed cut. It has 33 facets—nine on the crown and 24 making up the pavilion. The faceting of the crown is what makes the Tycoon Cut unique as the entire crown can be considered a nine facet table. The top center facet is in the shape of a diamond, making it the only diamond with a diamond on top.
The cut is a rectangular mixed cut. It has 33 facets—nine on the crown and 24 making up the pavilion. The faceting of the crown is what makes the Tycoon Cut unique as the entire crown can be considered a nine facet table. The top center facet is in the shape of a diamond, making it the only diamond with a diamond on top.
How To Judge Alexandrite (color change) Chrysoberyl
Color
- The primary consideration is the extent of color change. The most desirable color change is saturated ruby red (incandescent lighting) to saturated emerald green (day light or fluorescent light). Quite often the stones have color modifiers which may result in the reds having a purplish, and the greens a bluish secondary color.
- In most cases the saturation level of both hues is relatively low so stones that show colors of high intensity fetch higher premium.
Phenomenon
- The stone should display distinct change of color from an incandescent light source to a day light fluorescent one.
Clarity
- The clarity of the stone is a factor. Alexandrites may be heavily included; as long as the inclusions are not too distracting, the stone should be judged based on the unique color change.
Cut
- Alexandrites are usually faceted. If they a show a chatoyant phenomenon, they may be cut cabochon.
- The primary consideration is the extent of color change. The most desirable color change is saturated ruby red (incandescent lighting) to saturated emerald green (day light or fluorescent light). Quite often the stones have color modifiers which may result in the reds having a purplish, and the greens a bluish secondary color.
- In most cases the saturation level of both hues is relatively low so stones that show colors of high intensity fetch higher premium.
Phenomenon
- The stone should display distinct change of color from an incandescent light source to a day light fluorescent one.
Clarity
- The clarity of the stone is a factor. Alexandrites may be heavily included; as long as the inclusions are not too distracting, the stone should be judged based on the unique color change.
Cut
- Alexandrites are usually faceted. If they a show a chatoyant phenomenon, they may be cut cabochon.
Fiber Optic Technology
David R. Goff writes:
A Brief History of Fiber Optic Technology
Fiber optic technology experienced a phenomenal rate of progress in the second half of the twentieth century. Early success came during the 1950’s with the development of the fiberscope. This image-transmitting device, which used the first practical all-glass fiber, was concurrently devised by Brian O’Brien at the American Optical Company and Narinder Kapany (who first coined the term “fiber optics” in 1956) and colleagues at the Imperial College of Science and Technology in London. Early all-glass fibers experienced excessive optical loss, the loss of the light signal as it traveled the fiber, limiting transmission distances.
More info @ http://www.fiber-optics.info/fiber-history.htm
A Brief History of Fiber Optic Technology
Fiber optic technology experienced a phenomenal rate of progress in the second half of the twentieth century. Early success came during the 1950’s with the development of the fiberscope. This image-transmitting device, which used the first practical all-glass fiber, was concurrently devised by Brian O’Brien at the American Optical Company and Narinder Kapany (who first coined the term “fiber optics” in 1956) and colleagues at the Imperial College of Science and Technology in London. Early all-glass fibers experienced excessive optical loss, the loss of the light signal as it traveled the fiber, limiting transmission distances.
More info @ http://www.fiber-optics.info/fiber-history.htm
Raman Spectroscopy
Renishaw writes:
Users in research laboratories, development labs and production lines worldwide employ the microscopes and analysers in a diverse range of fields - for example, in the computer hard disc, pharmaceutical, polymer, semiconductor, and chemical industries. More exotic applications include the identification of drugs and explosives by forensic scientists, and the analysis of paint and pigments on historic works of art as an aid to accurate restoration.
Gemmologists are also using the Raman microscopes to identify gemstones, and to determine their source by analysing the tiny mineral inclusions contained within them.
Currently, there is much discussion in the gems community about a new heat-treatment for poor quality diamonds that changes their appearance to that of gem quality diamond. Fortunately, Renishaw Raman systems can reveal when this has occurred, ensuring that true diamond quality is maintained. Also, a variety of medical applications is being developed, one of the most notable being the detection of cancerous and pre-cancerous cells. In the near future, it is expected that small optical fibre probes and automated microscope systems will be used to acquire spectra from human tissue, allowing the rapid diagnosis of potential cancers as an outpatient procedure.
The capabilities of the instruments have been expanded to include a wider range of lasers, enhanced optical filtering systems, many new accessories, increased automation and improved software, making the instruments even easier to use. The number of applications will increase as Renishaw continues to develop new technologies in Raman spectroscopy.
More info @ http://www.renishaw.com/client/product/UKEnglish/PGP-37.shtml
Users in research laboratories, development labs and production lines worldwide employ the microscopes and analysers in a diverse range of fields - for example, in the computer hard disc, pharmaceutical, polymer, semiconductor, and chemical industries. More exotic applications include the identification of drugs and explosives by forensic scientists, and the analysis of paint and pigments on historic works of art as an aid to accurate restoration.
Gemmologists are also using the Raman microscopes to identify gemstones, and to determine their source by analysing the tiny mineral inclusions contained within them.
Currently, there is much discussion in the gems community about a new heat-treatment for poor quality diamonds that changes their appearance to that of gem quality diamond. Fortunately, Renishaw Raman systems can reveal when this has occurred, ensuring that true diamond quality is maintained. Also, a variety of medical applications is being developed, one of the most notable being the detection of cancerous and pre-cancerous cells. In the near future, it is expected that small optical fibre probes and automated microscope systems will be used to acquire spectra from human tissue, allowing the rapid diagnosis of potential cancers as an outpatient procedure.
The capabilities of the instruments have been expanded to include a wider range of lasers, enhanced optical filtering systems, many new accessories, increased automation and improved software, making the instruments even easier to use. The number of applications will increase as Renishaw continues to develop new technologies in Raman spectroscopy.
More info @ http://www.renishaw.com/client/product/UKEnglish/PGP-37.shtml
Wednesday, January 10, 2007
Bernd Munsteiner
Probably the most exciting development in gem cutting since the creation of the round brilliant is a style of gem cutting developed in the 1970's by Idar-Oberstein artist-craftsman extraordinaire, Bernd Munsteiner.
Today, Munsteiner's work has been widely copied and even mass produced. The generic style is known variously as the Munsteiner or Fantasy Cut. Stones display facets, but rather than being flat, they are arranged in v-shaped grooves somewhat similar to the striations on certain crystals. Combinations of flat facets and curved surfaces are also sometimes seen.
To know more about the Master cutter and jewelry designer, visit the following websites at:
www.khulsey.com/jewelry/atelier_munsteiner.html
www.munsteiner-cut.de
Today, Munsteiner's work has been widely copied and even mass produced. The generic style is known variously as the Munsteiner or Fantasy Cut. Stones display facets, but rather than being flat, they are arranged in v-shaped grooves somewhat similar to the striations on certain crystals. Combinations of flat facets and curved surfaces are also sometimes seen.
To know more about the Master cutter and jewelry designer, visit the following websites at:
www.khulsey.com/jewelry/atelier_munsteiner.html
www.munsteiner-cut.de
How To Judge Opal
Color
First of all, define the type of opal (black, semi-black, crystal, white, etc.) you are evaluating.
Questions to ask regarding color:
- Play-of-color and pattern of color (if applicable). What are the predominant colors? Reds, violets and oranges are more valuable than greens and blues. Red is the rarest, and if present, all other colors are possible. If blue is visible face-up, then other colors will not be possible. Also take into account the distribution, contrast and abundance of colors present.
- Grading opal patterns is quite subjective and may depend largely of the viewer's personal taste. Generally the more colors that appear to the viewer the more valuable the stone. Stones showing largely blue flash are least valuable.
-Pinfire, consisting of small dots of color is quite common, and not especially valuable, even if the predominant color is red.
-Flash refers to opals with color patterns that appear suddenly as the stone is moved.
-Harlequin refers to opals with a regular arrangement of similarly-sized flashes of color. The more regular the arrangement, the better. Stones showing the full range of colors in this pattern are exceedingly rare and valuable.
- Extinction : Does the full color range appear over a small viewing angle?
- In other words, is there an angle of extinction, during a 360x rotation, no colors are visible? Another way of describing this is directionality - the most valuable stones do not show any extinction of color.
- Brilliancy : How intense are the colors? Do they stand out from the background? How is the color distributed?
- Consider the amount of potch in comparison with the amount of play-of-color. Although potch provides a background for the play-of-color, we buy opal per carat, and so do not want to purchase opals with excessive amounts of potch (potch to play-of-color ratio).
- Sequence of colors : Red that holds over a wide range of viewing angles is the most desirable. In black opal, a red immediately followed by a royal blue is the rarest and most sought-after color sequence.
Practical Tip: Place the opal on a flat surface at arm's length; then rotate it through 360˚ noting the play-of-color, brilliance, and intensity of colors, symmetry and polish. Then hold the opal up to the light and estimate the ratio of potch to play-of-color.
Fine opals should show:
- Uniform play-of-color through 360º
- Intense, brilliant colors
- No 'extinction'
- Symmetrical cut, and fine degree of polish
Judge other opals from this ideal standpoint.
Clarity
Note the following:
- How transparent is the material? High transparency is sought after in light opal, but may reduce the value of black opal.
- Are any fragments of matrix present? Potch, fragments of host rock, sand or other impurities should not interrupt the play-of-color. Material should be free from blemishes visible from top.
- Are there any cracks and flaws visible? Precious opal can contain around 6-10% water and some opals from certain areas may craze, crack and/or turn opaque. Remember, never buy a cracked opal. The crack will only get worse as time passes.
Cut
In judging cut, look for the symmetry (proportions) and polish (finish). Is the make (cut and proportions) of the cabochon good? How good is the surface polish?
First of all, define the type of opal (black, semi-black, crystal, white, etc.) you are evaluating.
Questions to ask regarding color:
- Play-of-color and pattern of color (if applicable). What are the predominant colors? Reds, violets and oranges are more valuable than greens and blues. Red is the rarest, and if present, all other colors are possible. If blue is visible face-up, then other colors will not be possible. Also take into account the distribution, contrast and abundance of colors present.
- Grading opal patterns is quite subjective and may depend largely of the viewer's personal taste. Generally the more colors that appear to the viewer the more valuable the stone. Stones showing largely blue flash are least valuable.
-Pinfire, consisting of small dots of color is quite common, and not especially valuable, even if the predominant color is red.
-Flash refers to opals with color patterns that appear suddenly as the stone is moved.
-Harlequin refers to opals with a regular arrangement of similarly-sized flashes of color. The more regular the arrangement, the better. Stones showing the full range of colors in this pattern are exceedingly rare and valuable.
- Extinction : Does the full color range appear over a small viewing angle?
- In other words, is there an angle of extinction, during a 360x rotation, no colors are visible? Another way of describing this is directionality - the most valuable stones do not show any extinction of color.
- Brilliancy : How intense are the colors? Do they stand out from the background? How is the color distributed?
- Consider the amount of potch in comparison with the amount of play-of-color. Although potch provides a background for the play-of-color, we buy opal per carat, and so do not want to purchase opals with excessive amounts of potch (potch to play-of-color ratio).
- Sequence of colors : Red that holds over a wide range of viewing angles is the most desirable. In black opal, a red immediately followed by a royal blue is the rarest and most sought-after color sequence.
Practical Tip: Place the opal on a flat surface at arm's length; then rotate it through 360˚ noting the play-of-color, brilliance, and intensity of colors, symmetry and polish. Then hold the opal up to the light and estimate the ratio of potch to play-of-color.
Fine opals should show:
- Uniform play-of-color through 360º
- Intense, brilliant colors
- No 'extinction'
- Symmetrical cut, and fine degree of polish
Judge other opals from this ideal standpoint.
Clarity
Note the following:
- How transparent is the material? High transparency is sought after in light opal, but may reduce the value of black opal.
- Are any fragments of matrix present? Potch, fragments of host rock, sand or other impurities should not interrupt the play-of-color. Material should be free from blemishes visible from top.
- Are there any cracks and flaws visible? Precious opal can contain around 6-10% water and some opals from certain areas may craze, crack and/or turn opaque. Remember, never buy a cracked opal. The crack will only get worse as time passes.
Cut
In judging cut, look for the symmetry (proportions) and polish (finish). Is the make (cut and proportions) of the cabochon good? How good is the surface polish?
Tuesday, January 09, 2007
Refractometer
The instrument in general use for the measurement of refractive index is the refractometer. The refractometer determines the refractive index of a gemstone by using the principle of critical angle of total internal reflection, which is used to measure the refractive indices of various substances.
General information
- Refractive Index (RI) measurement is the most useful and accurate means of testing gemstones.
- It is convenient, non-destructive and relatively quick to carry out providing useful information.
Requirements
- Optical contact.
- Clean, polished surface.
- Contact liquid.
- Refractive index (RI) of the stone under test should be within the range of the instrument.
Limits
- Upper limit of the refractometer is determined by the refractive index of the prism as well as the refractive index of the contact fluid / medium.
- In a normal commercial refractometer, this is 1.81 (some RI liquids may have a limit of 1.79).
Results
- Flat surface readings: single refractive (SR) / double refractive (DR), birefringence, optic character (uniaxial or biaxial), and optic sign (positive or negative).
- Curved surface readings (distant vision method): Mean refractive index only.
General information
- Refractive Index (RI) measurement is the most useful and accurate means of testing gemstones.
- It is convenient, non-destructive and relatively quick to carry out providing useful information.
Requirements
- Optical contact.
- Clean, polished surface.
- Contact liquid.
- Refractive index (RI) of the stone under test should be within the range of the instrument.
Limits
- Upper limit of the refractometer is determined by the refractive index of the prism as well as the refractive index of the contact fluid / medium.
- In a normal commercial refractometer, this is 1.81 (some RI liquids may have a limit of 1.79).
Results
- Flat surface readings: single refractive (SR) / double refractive (DR), birefringence, optic character (uniaxial or biaxial), and optic sign (positive or negative).
- Curved surface readings (distant vision method): Mean refractive index only.
Diamond Cut: STARBURST
The Starburst Cut name is a patent of Louis Glick & Co and U Doppelt & Co, developed 25 years ago by the Louis Glick and U Doppelt companies.
The Starburst is a modified radiant cut. It is a rectangular brilliant cut with 88 or more kite and star shaped facets. Often there are twice as many facets on a Starburst as on a traditional round cut.
The Starburst is a modified radiant cut. It is a rectangular brilliant cut with 88 or more kite and star shaped facets. Often there are twice as many facets on a Starburst as on a traditional round cut.
Tasmanian Sapphire
David Federman writes:
Australia was to sapphire in the 1980s what South Africa was to diamonds for more than a century. Still, no one felt blue when Aussie indigos disappeared under a blanket of Madagascar's dressier blues in the 1990s.
The new African corundum boasted color that begged comparison to that of Sri Lankan goods—even on occasion Kashmir classics. Australia's material, on the other hand, was lucky to inspire comparisons to dark but sometimes handsome Cambodian and Thai stones. No wonder Australia came and went as a corundum colossus and no one shed a tear.
More info @ http://archives.modernjeweler.com/publication/article.jsp?pubId=1&id=193
Australia was to sapphire in the 1980s what South Africa was to diamonds for more than a century. Still, no one felt blue when Aussie indigos disappeared under a blanket of Madagascar's dressier blues in the 1990s.
The new African corundum boasted color that begged comparison to that of Sri Lankan goods—even on occasion Kashmir classics. Australia's material, on the other hand, was lucky to inspire comparisons to dark but sometimes handsome Cambodian and Thai stones. No wonder Australia came and went as a corundum colossus and no one shed a tear.
More info @ http://archives.modernjeweler.com/publication/article.jsp?pubId=1&id=193
The Colored Stone Story
What are colored stones?
Colored stones refer to any gem other than diamond. Some diamonds are colored, but colored diamonds are not considered colored stones.
What are the attributes of colored stones?
A colored stone possesses any of these three key characteristics: beauty, durability and rarity. An ideal colored stone has all three characteristics.
Why do colored stones look the way they do?
A number of factors contribute to the overall appearance of colored stones. These include color, transparency, lustre, brilliance, dispersion, scintillation, clarity and cut.
What is the difference between precious stones and semi-precious stones?
In the past, the term ‘precious stone’ referred to diamond, emerald, ruby and sapphire, while ‘semi-precious stone’ were anything other than these. Then, precious and semi-precious stones indicated relative value – the former being more valuable. Today, these descriptions have little meaning in terms of value, since all colored stones come in a variety of qualities. For example, a low quality ruby may sell for as little as USD1 per carat, while a good quality demantoid garnet may fetch USD1,000 per carat.
Are colored stones durable?
In order to wear well and retain attractiveness colored stones should be durable. Durability includes hardness and toughness. Resistance to scratching is referred to as hardness. Some colored stones are soft and may be easily scratched, thereby losing their attractiveness. Ideally a colored stone should be harder than dust particles, which may be fine particles of quartz (hardness=7) found in the air. Colored stones with hardness greater than quartz include ruby, sapphire, topaz, tourmaline, spinel and garnet. These are the most valuable. Resistance to breakage is referred to as toughness, and this depends on colored stone’s structure. Extremely tough gems are usually aggregates such as jadeite and nephrite.
Is there a relationship between quality and price?
In a perfect world price would directly relate to quality, weight and rarity. The real world is far from perfect. Market factors may have an impact on prices, as does quality.
What is colored stone treatment?
Colored stone treatment is a common term. It describes different ways to improve the beauty of colored stones. Colored stones have been enhanced for thousands of years. The truth is there isn’t enough top quality colored stones being mined to meet demand. Enhancement increases supply, ensuring a constant flow of colored stones which we can afford and enjoy. If in doubt about a colored stone, always consult a reputed gem testing laboratory.
Colored stones refer to any gem other than diamond. Some diamonds are colored, but colored diamonds are not considered colored stones.
What are the attributes of colored stones?
A colored stone possesses any of these three key characteristics: beauty, durability and rarity. An ideal colored stone has all three characteristics.
Why do colored stones look the way they do?
A number of factors contribute to the overall appearance of colored stones. These include color, transparency, lustre, brilliance, dispersion, scintillation, clarity and cut.
What is the difference between precious stones and semi-precious stones?
In the past, the term ‘precious stone’ referred to diamond, emerald, ruby and sapphire, while ‘semi-precious stone’ were anything other than these. Then, precious and semi-precious stones indicated relative value – the former being more valuable. Today, these descriptions have little meaning in terms of value, since all colored stones come in a variety of qualities. For example, a low quality ruby may sell for as little as USD1 per carat, while a good quality demantoid garnet may fetch USD1,000 per carat.
Are colored stones durable?
In order to wear well and retain attractiveness colored stones should be durable. Durability includes hardness and toughness. Resistance to scratching is referred to as hardness. Some colored stones are soft and may be easily scratched, thereby losing their attractiveness. Ideally a colored stone should be harder than dust particles, which may be fine particles of quartz (hardness=7) found in the air. Colored stones with hardness greater than quartz include ruby, sapphire, topaz, tourmaline, spinel and garnet. These are the most valuable. Resistance to breakage is referred to as toughness, and this depends on colored stone’s structure. Extremely tough gems are usually aggregates such as jadeite and nephrite.
Is there a relationship between quality and price?
In a perfect world price would directly relate to quality, weight and rarity. The real world is far from perfect. Market factors may have an impact on prices, as does quality.
What is colored stone treatment?
Colored stone treatment is a common term. It describes different ways to improve the beauty of colored stones. Colored stones have been enhanced for thousands of years. The truth is there isn’t enough top quality colored stones being mined to meet demand. Enhancement increases supply, ensuring a constant flow of colored stones which we can afford and enjoy. If in doubt about a colored stone, always consult a reputed gem testing laboratory.
The Chelsea Color Filter
The Chelsea Color Filter was first developed by the Gem Testing Laboratory of the London Chamber of Commerce (now GAGTL/Gem-A) in 1934, and was first used at the Chelsea College of Science and Technology as an aid in the separation of emerald from its simulants. It was originally called an emerald filter.
The Chelsea filter consists of a combination of two gelatin filters that pass wavelengths in the deep red and in the yellow green. To obtain best results, stones should be viewed under a strong artificial light with the filter held close to the eye so as to cut out any outside glare of light. The gemological uses of this simple instrument are limited, but it can be useful in certain circumstances.
The chromium in emerald makes it appear reddish or pinkish when the stone is strongly illuminated and viewed through the filter. Emerald imitations that do not contain chromium appear green through filter. A few natural emeralds, especially those from South America, fail to show pink through the filter. Once synthetic emeralds appeared on the market, the Chelsea filter became less useful as an emerald filter, because the synthetic product, also containing chromium, appears red through the filter, though often of a deeper red than natural counterparts.
The Chelsea filter is also useful in separating cobalt-containing gem species from others, as the presence of cobalt results in a red reaction through the filter. Gemstones colored by cobalt are in the main synthetic or man-made, and appear red through the filter. This has proven useful in separating synthetic blue spinel and man-made blue glass from the stones they imitate, namely aquamarine, blue zircon and sapphire. Gemstones containing cobalt are rare on earth.
Aquamarine and its most common simulant, synthetic blue spinela are visually very similar, but owe their respective blue color to different causes. Aquamarine is colored by iron, which absorbs red wavelengths and transmits some green wavelengths, and appears green through the filter. Synthetic blue spinel is colored by cobalt which absorbs green wavelength, but transmits red wavelength, appears red through the filter.
The absorption spectrum of aquamarine, colord by iron, and synthetic blue spinel, colored by cobalt, can help us understand why their reactions to the Chelsea filter are so different.
The Chelsea filter consists of a combination of two gelatin filters that pass wavelengths in the deep red and in the yellow green. To obtain best results, stones should be viewed under a strong artificial light with the filter held close to the eye so as to cut out any outside glare of light. The gemological uses of this simple instrument are limited, but it can be useful in certain circumstances.
The chromium in emerald makes it appear reddish or pinkish when the stone is strongly illuminated and viewed through the filter. Emerald imitations that do not contain chromium appear green through filter. A few natural emeralds, especially those from South America, fail to show pink through the filter. Once synthetic emeralds appeared on the market, the Chelsea filter became less useful as an emerald filter, because the synthetic product, also containing chromium, appears red through the filter, though often of a deeper red than natural counterparts.
The Chelsea filter is also useful in separating cobalt-containing gem species from others, as the presence of cobalt results in a red reaction through the filter. Gemstones colored by cobalt are in the main synthetic or man-made, and appear red through the filter. This has proven useful in separating synthetic blue spinel and man-made blue glass from the stones they imitate, namely aquamarine, blue zircon and sapphire. Gemstones containing cobalt are rare on earth.
Aquamarine and its most common simulant, synthetic blue spinela are visually very similar, but owe their respective blue color to different causes. Aquamarine is colored by iron, which absorbs red wavelengths and transmits some green wavelengths, and appears green through the filter. Synthetic blue spinel is colored by cobalt which absorbs green wavelength, but transmits red wavelength, appears red through the filter.
The absorption spectrum of aquamarine, colord by iron, and synthetic blue spinel, colored by cobalt, can help us understand why their reactions to the Chelsea filter are so different.
Monday, January 08, 2007
Tsavorite Garnet
National Jeweler Network writes:
Michael Coach and Associates has announced that it has acquired the largest clean tsavorite in the world. The stone weighs 325.13 carats and will be on display at the American Gem Trade Association GemFair beginning at the end of January in Tucson, Ariz.
The stone was found in the Karo area of Mereloni, Tanzania, in what is believed to be the biggest pocket of tsavorite ever discovered. The rough was found in a mine that goes straight down 120 meters from the surface and follows a reef at a 45-degree angle to a final depth of 180 meters.
Tsavorite is usually found in a host matrix of diopside, zoisite and grossular garnet, and is normally made in small nodules of gem crystal, which are put under enormous pressure. Because the nodules are squeezed and pushed during growth, inclusions are easily formed, making clean crystals something of a rarity.
From the rough, four stones were cut: a 62-carat clean, a 120-carat clean, a 307-carat included and the 325.13-carat clean acquired by Michael Couch and Associates. Asking price on the 325.13-carat stone is $2.2 million.
More info @ http://www.nationaljewelernetwork.com/njn/content_display/colored_stones/e3i359161611ed1086efe5914532f3faa3e
Michael Coach and Associates has announced that it has acquired the largest clean tsavorite in the world. The stone weighs 325.13 carats and will be on display at the American Gem Trade Association GemFair beginning at the end of January in Tucson, Ariz.
The stone was found in the Karo area of Mereloni, Tanzania, in what is believed to be the biggest pocket of tsavorite ever discovered. The rough was found in a mine that goes straight down 120 meters from the surface and follows a reef at a 45-degree angle to a final depth of 180 meters.
Tsavorite is usually found in a host matrix of diopside, zoisite and grossular garnet, and is normally made in small nodules of gem crystal, which are put under enormous pressure. Because the nodules are squeezed and pushed during growth, inclusions are easily formed, making clean crystals something of a rarity.
From the rough, four stones were cut: a 62-carat clean, a 120-carat clean, a 307-carat included and the 325.13-carat clean acquired by Michael Couch and Associates. Asking price on the 325.13-carat stone is $2.2 million.
More info @ http://www.nationaljewelernetwork.com/njn/content_display/colored_stones/e3i359161611ed1086efe5914532f3faa3e
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