The diamonds selected for the annual Argyle Pink Diamond Tender are one-of-a-kind lot and are extremely rare. In 2006, out of 30 millions +/- carats produced by the Argyle mine only 65 stones met the Tender standards. The Tender collection included 65 natural pink and blue diamonds weighing approximately 61.43 carats. The diamonds are processed by skilled diamond cutters at the Argyle’s polishing factory in Perth.
Once a year, Argyle’s diamond marketing team issue special release on pink diamonds that are sold by special bids by invitation only. Argyle has sold pink diamonds for up to $1 million a carat. The Argyle pink diamond color ranges from various shades of pink to intense purplish red. The value is based on the intensity of color. The top quality stones are faceted into round, marquise, oval, or pear to improve the over all life and natural beauty. Demand for Argyle’s fancy pink diamonds are extremely high and collectors from around the world pay hefty premiums to buy them.
Sunday, February 11, 2007
The GodFather Movie
Memorable quote (s) from the movie:
Don Corleone (Marlon Brando): I never wanted this for you. I work my whole life - I don't apologize - to take care of my family, and I refused to be a fool, dancing on the string held by all those bigshots. I don't apologize - that's my life - but I thought that, that when it was your time, that you would be the one to hold the string. Senator Corleone; Governor Corleone. Well, it wasn't enough time, Michael. It wasn't enough time.
Michael (Al Pacino): We'll get there, pop. We'll get there.
Don Corleone (Marlon Brando): I never wanted this for you. I work my whole life - I don't apologize - to take care of my family, and I refused to be a fool, dancing on the string held by all those bigshots. I don't apologize - that's my life - but I thought that, that when it was your time, that you would be the one to hold the string. Senator Corleone; Governor Corleone. Well, it wasn't enough time, Michael. It wasn't enough time.
Michael (Al Pacino): We'll get there, pop. We'll get there.
The Federal Trade Commission’s Guide for the Jewelry, Precious Metals and Pewter Industries
FTC writes:
23.17 Misrepresentation of weight and "total weight."
(a) It is unfair or deceptive to misrepresent the weight of a diamond.
(b) It is unfair or deceptive to use the word "point" or any abbreviation in any representation, advertising, marking, or labeling to describe the weight of a diamond, unless the weight is also stated as decimal parts of a carat (e.g., 25 points or .25 carat).
Note 1 to paragraph (b): A carat is a standard unit of weight for a diamond and is equivalent to 200 milligrams (1/5 gram). A point is one one hundredth (1/100) of a carat.
(c) If diamond weight is stated as decimal parts of a carat (e.g., .47 carat), the stated figure should be accurate to the last decimal place. If diamond weight is stated to only one decimal place (e.g., .5 carat), the stated figure should be accurate to the second decimal place (e.g., ".5 carat" could represent a diamond weight between .495-.504).
(d) If diamond weight is stated as fractional parts of a carat, a conspicuous disclosure of the fact that the diamond weight is not exact should be made in close proximity to the fractional representation and a disclosure of a reasonable range of weight for each fraction (or the weight tolerance being used) should also be made.
Note to paragraph (d): When fractional representations of diamond weight are made, as described in paragraph d of this section, in catalogs or other printed materials, the disclosure of the fact that the actual diamond weight is within a specified range should be made conspicuously on every page where a fractional representation is made. Such disclosure may refer to a chart or other detailed explanation of the actual ranges used. For example, "Diamond weights are not exact; see chart on p.X for ranges."
More info @ http://www.ftc.gov/bcp/guides/jewel-gd.htm
23.17 Misrepresentation of weight and "total weight."
(a) It is unfair or deceptive to misrepresent the weight of a diamond.
(b) It is unfair or deceptive to use the word "point" or any abbreviation in any representation, advertising, marking, or labeling to describe the weight of a diamond, unless the weight is also stated as decimal parts of a carat (e.g., 25 points or .25 carat).
Note 1 to paragraph (b): A carat is a standard unit of weight for a diamond and is equivalent to 200 milligrams (1/5 gram). A point is one one hundredth (1/100) of a carat.
(c) If diamond weight is stated as decimal parts of a carat (e.g., .47 carat), the stated figure should be accurate to the last decimal place. If diamond weight is stated to only one decimal place (e.g., .5 carat), the stated figure should be accurate to the second decimal place (e.g., ".5 carat" could represent a diamond weight between .495-.504).
(d) If diamond weight is stated as fractional parts of a carat, a conspicuous disclosure of the fact that the diamond weight is not exact should be made in close proximity to the fractional representation and a disclosure of a reasonable range of weight for each fraction (or the weight tolerance being used) should also be made.
Note to paragraph (d): When fractional representations of diamond weight are made, as described in paragraph d of this section, in catalogs or other printed materials, the disclosure of the fact that the actual diamond weight is within a specified range should be made conspicuously on every page where a fractional representation is made. Such disclosure may refer to a chart or other detailed explanation of the actual ranges used. For example, "Diamond weights are not exact; see chart on p.X for ranges."
More info @ http://www.ftc.gov/bcp/guides/jewel-gd.htm
Principles Of Color Technology
By Fred W Billmeyer, Jr & Max Saltzman
John Wiley & Sons
1981 ISBN 0-471-03052-X
John Wiley & Sons writes:
In the fifteen years since the first edition of Principles of Color Technology, basic theory has remained the same, but in many cases practice has become considerably more automated. The second edition of this standard work covers all the major advances in color applied to the use of colorants in the industrial and creative production of colored material.
Billmeyer and Saltzman have substantially realigned their emphases in accordance with these new developments, including coverage of:
- Metamerism
- Non-color problems—quality control, techniques of sampling and sample preparation, and applications of simple statistics.
- Methods for instrument selection.
Fundamentals—the role of light, descriptions of color in objective, numerical terms, and practical industrial applications of color technology—are covered in the same methodical manner that has made Principles of Color Technology such an important information source for both industry and academics. Current updated material and a refinement of the general presentation make this second edition even more indispensable to the world of color technology.
John Wiley & Sons
1981 ISBN 0-471-03052-X
John Wiley & Sons writes:
In the fifteen years since the first edition of Principles of Color Technology, basic theory has remained the same, but in many cases practice has become considerably more automated. The second edition of this standard work covers all the major advances in color applied to the use of colorants in the industrial and creative production of colored material.
Billmeyer and Saltzman have substantially realigned their emphases in accordance with these new developments, including coverage of:
- Metamerism
- Non-color problems—quality control, techniques of sampling and sample preparation, and applications of simple statistics.
- Methods for instrument selection.
Fundamentals—the role of light, descriptions of color in objective, numerical terms, and practical industrial applications of color technology—are covered in the same methodical manner that has made Principles of Color Technology such an important information source for both industry and academics. Current updated material and a refinement of the general presentation make this second edition even more indispensable to the world of color technology.
The Slovak Opal
Dr Luigi Constantini, geologist and gemologist with the International Gemological Institute Italy, has written The Slovak Opal: A Rediscovery of the Queen of Gems for Gem Lovers and Tourists.
The book describes the historical as well as mineralogical and gemological aspect of Slovak opal. The book also explains the classification of Slovak opal, quality grading with glossary and index for quick reference.
The book is available @ www.e-igi.com/estore
The book describes the historical as well as mineralogical and gemological aspect of Slovak opal. The book also explains the classification of Slovak opal, quality grading with glossary and index for quick reference.
The book is available @ www.e-igi.com/estore
The Federal Trade Commission’s Guide for the Jewelry, Precious Metals and Pewter Industries
FTC writes:
23.16 Misuse of the words "brilliant" and "full cut."
It is unfair or deceptive to use the unqualified expressions "brilliant," "brilliant cut," or "full cut" to describe, identify, or refer to any diamond except a round diamond that has at least thirty-two (32) facets plus the table above the girdle and at least twenty-four (24) facets below.
Note to 23.16: Such terms should not be applied to single or rose-cut diamonds. They may be applied to emerald-(rectangular) cut, pear-shaped, heart-shaped, oval-shaped, and marquise-(pointed oval) cut diamonds meeting the above-stated facet requirements when, in immediate conjunction with the term used, the form of the diamond is disclosed.
More info @ http://www.ftc.gov/bcp/guides/jewel-gd.htm
23.16 Misuse of the words "brilliant" and "full cut."
It is unfair or deceptive to use the unqualified expressions "brilliant," "brilliant cut," or "full cut" to describe, identify, or refer to any diamond except a round diamond that has at least thirty-two (32) facets plus the table above the girdle and at least twenty-four (24) facets below.
Note to 23.16: Such terms should not be applied to single or rose-cut diamonds. They may be applied to emerald-(rectangular) cut, pear-shaped, heart-shaped, oval-shaped, and marquise-(pointed oval) cut diamonds meeting the above-stated facet requirements when, in immediate conjunction with the term used, the form of the diamond is disclosed.
More info @ http://www.ftc.gov/bcp/guides/jewel-gd.htm
Gemstones And Their Origins
By Peter C Keller
Van Nostrand Reinhold
1990 ISBN 0-442-31945-2
Van Nostrand Reinhold writes:
The closest most people ever come to experiencing gemstones at their source is at the jeweler’s case. This book takes you to many of their classic sources: the rich alluvial deposits of Sri Lanka, where precious stones lie exposed on gravel riverbeds; to Chantaburi-Trat, Thailand, where rubies are brought to the earth’s surface embedded in volcanic magma; to the black emerald-bearing veins of Muzo, Colombia; to the source of Australia’s Argyle diamond deposit—the most productive in the world, yet undiscovered until 1980.
Gemstones and Their Origins is the first major work devoted to the origins of precious stones: how they form, where they are found, and how they are recovered. Rigorous in scientific detail and lavish in illustrations, it explores the major geological processes responsible for the formation of gem deposits and then examines, on location, nine classic gem deposits from around the globe.
Peter C Keller takes you on a geologist’s tour of the world’s most famous and geologically significant gem deposits. Keller traces the origin of gems at each of four principle gem forming sources. First, we view the development of gemstones deposited by water on the earth’s surface. Here we encounter the gem gravels of Sri Lanka, opal deposits of Australia, and ruby and zircon from Indochina.
Next, we explore gemstones formed by molten rock—the hydrothermal emerald deposits of Colombia, the pegmatites of Minas Gerais, Brazil, and the rubies of Chantaburi-Trat in Thailand, brought to the earth’s surface in volcanic flows. As we go deeper into the earth’s crust, we encounter the world famous ruby deposits of Mogok, Burma, and jade deposits of northern Burma, one of few known examples of high pressure regional metamorphism.
Our descent into the earth’s crust ends some 100 miles below the earth’s surface. Here, in conditions of super high pressure and temperature, peridot and diamond form. Examples from the classic peridot of Zabargad and the recently discovered diamonds at Argyle in Western Australia are examined.
Along the way, Peter Keller documents this geological field trip with the outstanding photographs of Harold and Erica Van Pelt, renowned as the leading photographers of gems and mineral specimens in the world today. More than 100 stunning color photographs depict rough and cut stones and the often primitive places where they are mined. Useful maps, some in color, and an exhaustive bibliography make this the definitive reference work on the subject for gemologists and geologists, collectors and dealers, students and gem lovers.
Van Nostrand Reinhold
1990 ISBN 0-442-31945-2
Van Nostrand Reinhold writes:
The closest most people ever come to experiencing gemstones at their source is at the jeweler’s case. This book takes you to many of their classic sources: the rich alluvial deposits of Sri Lanka, where precious stones lie exposed on gravel riverbeds; to Chantaburi-Trat, Thailand, where rubies are brought to the earth’s surface embedded in volcanic magma; to the black emerald-bearing veins of Muzo, Colombia; to the source of Australia’s Argyle diamond deposit—the most productive in the world, yet undiscovered until 1980.
Gemstones and Their Origins is the first major work devoted to the origins of precious stones: how they form, where they are found, and how they are recovered. Rigorous in scientific detail and lavish in illustrations, it explores the major geological processes responsible for the formation of gem deposits and then examines, on location, nine classic gem deposits from around the globe.
Peter C Keller takes you on a geologist’s tour of the world’s most famous and geologically significant gem deposits. Keller traces the origin of gems at each of four principle gem forming sources. First, we view the development of gemstones deposited by water on the earth’s surface. Here we encounter the gem gravels of Sri Lanka, opal deposits of Australia, and ruby and zircon from Indochina.
Next, we explore gemstones formed by molten rock—the hydrothermal emerald deposits of Colombia, the pegmatites of Minas Gerais, Brazil, and the rubies of Chantaburi-Trat in Thailand, brought to the earth’s surface in volcanic flows. As we go deeper into the earth’s crust, we encounter the world famous ruby deposits of Mogok, Burma, and jade deposits of northern Burma, one of few known examples of high pressure regional metamorphism.
Our descent into the earth’s crust ends some 100 miles below the earth’s surface. Here, in conditions of super high pressure and temperature, peridot and diamond form. Examples from the classic peridot of Zabargad and the recently discovered diamonds at Argyle in Western Australia are examined.
Along the way, Peter Keller documents this geological field trip with the outstanding photographs of Harold and Erica Van Pelt, renowned as the leading photographers of gems and mineral specimens in the world today. More than 100 stunning color photographs depict rough and cut stones and the often primitive places where they are mined. Useful maps, some in color, and an exhaustive bibliography make this the definitive reference work on the subject for gemologists and geologists, collectors and dealers, students and gem lovers.
Saturday, February 10, 2007
Consumption Level Goes North As India Shines
(via Times News Network) Rajesh Shukla & Preeti Kakar writes:
The Indian economy has ushered in a new era, wherein the country’s per capita income growth in recent years has outperformed that of the other major Asian economies. However, the gains of prosperity have been distributed unevenly. The paradox of plenty amid poverty ceases to lift. For instance, per capita income in the richest state of the country is about five times that of the poorest.
India’s economic diversity matches its social diversity and this engenders a wide spectrum of consumers in terms of their income levels and spending behaviour. What is noteworthy here is that the diversity is not only visible in the spending behaviour of people with different levels of income but also with the same level of income. This is because income levels by themselves do not reveal much about market behaviour and purchasing power.
More info @ http://economictimes.indiatimes.com/articleshow/1581481.cms
The Indian economy has ushered in a new era, wherein the country’s per capita income growth in recent years has outperformed that of the other major Asian economies. However, the gains of prosperity have been distributed unevenly. The paradox of plenty amid poverty ceases to lift. For instance, per capita income in the richest state of the country is about five times that of the poorest.
India’s economic diversity matches its social diversity and this engenders a wide spectrum of consumers in terms of their income levels and spending behaviour. What is noteworthy here is that the diversity is not only visible in the spending behaviour of people with different levels of income but also with the same level of income. This is because income levels by themselves do not reveal much about market behaviour and purchasing power.
More info @ http://economictimes.indiatimes.com/articleshow/1581481.cms
Friday, February 09, 2007
Garnet And Glass Doublet
A garnet and glass doublet, also known as garnet-topped doublet (GTD) consists of a thin cap of almandine garnet fused to a piece of colored glass imitating a gem. The doublet was popular in the 18th and 19th century, and may still turn up in antique jewelry today.
The reason for constructing this type of doublet is to increase the surface luster on the table of a gemstone. For those who are unaware may think the stone is valuable, but it is easily detectable by the following means.
- The first step is to clean and examine the stone. Visual observation provides you with the chance to examine and classify all aspects of the physical appearance of the gem.
- Check the refractive index. Refractive index of the table will be that of almandine (1.76 or above).
- Refractive index of any pavilion facet will be within the glass range (1.50 - 1.70).
- Use the microscope. The luster difference between garnet top and the glass will become obvious.
- Do the red-ring test by placing the garnet-topped doublet face down on a white background. You will see a faint red ring inside the girdle outline representing the boundary of the garnet cap.
- Immersion technique. When you immerse the stone in a suitable liquid, you are able to see any color difference between the two materials.
- Fluorescence. This is a complimentary test. View the gem parallel to the girdle plane under long wave and short wave ultraviolet light. Garnet will show inert reaction, while glass may show chalky fluorescence.
The reason for constructing this type of doublet is to increase the surface luster on the table of a gemstone. For those who are unaware may think the stone is valuable, but it is easily detectable by the following means.
- The first step is to clean and examine the stone. Visual observation provides you with the chance to examine and classify all aspects of the physical appearance of the gem.
- Check the refractive index. Refractive index of the table will be that of almandine (1.76 or above).
- Refractive index of any pavilion facet will be within the glass range (1.50 - 1.70).
- Use the microscope. The luster difference between garnet top and the glass will become obvious.
- Do the red-ring test by placing the garnet-topped doublet face down on a white background. You will see a faint red ring inside the girdle outline representing the boundary of the garnet cap.
- Immersion technique. When you immerse the stone in a suitable liquid, you are able to see any color difference between the two materials.
- Fluorescence. This is a complimentary test. View the gem parallel to the girdle plane under long wave and short wave ultraviolet light. Garnet will show inert reaction, while glass may show chalky fluorescence.
Gems And Gem Art
Programa Royal Collections Group writes:
Gazing at the world’s biggest topaz, enjoying the rare sight of a gem embedded in a meteorite or marvelling at centuries-old sculptures made from precious stones are all culturally enriching experiences for people from all walks of life.
But the aim of PRC (Programa Royal Collection) is not only to exhibit unique collections but also to convert these experiences into a discovering and learning process that goes well beyond mere passive observation. This twofold experience of enjoying and learning in tandem is the keynote idea of our exhibition philosophy.
In the case of the gem exhibitions, for example, the precious stones are accompanied with educational display cases containing such exhibits as gemmological maps, uncut gems, laboratory material, polishing and cutting equipment, etc., all designed to raise public awareness of gems and gem art. These display cases are backed up by a wealth of informative material in different languages and with different levels of specialisation: posters for display cases, information panels, photographs, fact files, brochures, catalogues, etc. Visitors are thus enabled to discover numerous aspects of the world of gems, such as their formation, mining, physical characteristics (hardness, optical effects, cleavage...), cutting, authentication, what makes a synthetic gem different from a false gem and many other fascinating facts and snippets.
More info @ http://www.royalcollections.es/ingles/queofreceprc/interesdidactico/interesdidactico.htm
Gazing at the world’s biggest topaz, enjoying the rare sight of a gem embedded in a meteorite or marvelling at centuries-old sculptures made from precious stones are all culturally enriching experiences for people from all walks of life.
But the aim of PRC (Programa Royal Collection) is not only to exhibit unique collections but also to convert these experiences into a discovering and learning process that goes well beyond mere passive observation. This twofold experience of enjoying and learning in tandem is the keynote idea of our exhibition philosophy.
In the case of the gem exhibitions, for example, the precious stones are accompanied with educational display cases containing such exhibits as gemmological maps, uncut gems, laboratory material, polishing and cutting equipment, etc., all designed to raise public awareness of gems and gem art. These display cases are backed up by a wealth of informative material in different languages and with different levels of specialisation: posters for display cases, information panels, photographs, fact files, brochures, catalogues, etc. Visitors are thus enabled to discover numerous aspects of the world of gems, such as their formation, mining, physical characteristics (hardness, optical effects, cleavage...), cutting, authentication, what makes a synthetic gem different from a false gem and many other fascinating facts and snippets.
More info @ http://www.royalcollections.es/ingles/queofreceprc/interesdidactico/interesdidactico.htm
All About Eve
A memorable quote from the movie:
Margo Channing (Bette Davis): Funny business, a woman's career, the things you drop on the way up the ladder so you can move faster. You forget you'll need them again when you get back to being a woman. It's one career all females have in common - being a woman. Sooner or later we've got to work at it no matter how many other careers we've had or wanted. And in the last analysis nothing is any good unless you can look up just before dinner or turn around in bed and there he is. Without that you're not a woman. You're something with a French provincial office or a book full of clippings but you're not a woman. Slow curtain, the end.
Margo Channing (Bette Davis): Funny business, a woman's career, the things you drop on the way up the ladder so you can move faster. You forget you'll need them again when you get back to being a woman. It's one career all females have in common - being a woman. Sooner or later we've got to work at it no matter how many other careers we've had or wanted. And in the last analysis nothing is any good unless you can look up just before dinner or turn around in bed and there he is. Without that you're not a woman. You're something with a French provincial office or a book full of clippings but you're not a woman. Slow curtain, the end.
The Federal Trade Commission’s Guide for the Jewelry, Precious Metals and Pewter Industries
FTC writes:
23.15 Misuse of the term "properly cut," etc.
It is unfair or deceptive to use the terms "properly cut," "proper cut," "modern cut," or any representation of similar meaning to describe any diamond that is lopsided, or is so thick or so thin in depth as to detract materially from the brilliance of the stone.
Note to 23.15: Stones that are commonly called "fisheye" or "old mine" should not be described as "properly cut," "modern cut," etc.
More info @ http://www.ftc.gov/bcp/guides/jewel-gd.htm
23.15 Misuse of the term "properly cut," etc.
It is unfair or deceptive to use the terms "properly cut," "proper cut," "modern cut," or any representation of similar meaning to describe any diamond that is lopsided, or is so thick or so thin in depth as to detract materially from the brilliance of the stone.
Note to 23.15: Stones that are commonly called "fisheye" or "old mine" should not be described as "properly cut," "modern cut," etc.
More info @ http://www.ftc.gov/bcp/guides/jewel-gd.htm
Methuen Handbook of Color
By A Korenerup & J H Wanscher
Politikens Forlag, Copenhagen
Methuen London
1961 / 1989 ISBN 0-413-33400-7
Methuen writes:
The third edition of this authoritative pocket color book covers the essentials of color practice and includes an international dictionary of colors with British standard equivalents. A universal ready reference for all those whose jobs or recreation involves color, it now includes names of colors used by British paint manufacturers and colors traditionally associated with the printing ink industry, thus shedding light on the whole field of color in art and science.
The color book is divided into two parts, the Handbook proper and a Color Dictionary. The Handbook explains the basic facts upon which all systems of color identification are based, and describes some important visual effects that apply to color usage generally. The Dictionary consists of plates of 1266 color samples accompanied by descriptive glossaries of color names with an easy cross reference system.
The Color Dictionary is so contrived that a color sample of one’s own can be compared with the charted samples, and an appropriate name selected for it from the color diagrams. On the other hand, the appearance of a named color can be discovered by looking up the color name in alphabetical list and following the reference symbol to the appropriate place on the color plates.
Lists of color names used by British paint manufacturers and those used by the printing ink industry are included, set out in such a way that they can be readily compared with the colors reproduced in the Dictionary.
Politikens Forlag, Copenhagen
Methuen London
1961 / 1989 ISBN 0-413-33400-7
Methuen writes:
The third edition of this authoritative pocket color book covers the essentials of color practice and includes an international dictionary of colors with British standard equivalents. A universal ready reference for all those whose jobs or recreation involves color, it now includes names of colors used by British paint manufacturers and colors traditionally associated with the printing ink industry, thus shedding light on the whole field of color in art and science.
The color book is divided into two parts, the Handbook proper and a Color Dictionary. The Handbook explains the basic facts upon which all systems of color identification are based, and describes some important visual effects that apply to color usage generally. The Dictionary consists of plates of 1266 color samples accompanied by descriptive glossaries of color names with an easy cross reference system.
The Color Dictionary is so contrived that a color sample of one’s own can be compared with the charted samples, and an appropriate name selected for it from the color diagrams. On the other hand, the appearance of a named color can be discovered by looking up the color name in alphabetical list and following the reference symbol to the appropriate place on the color plates.
Lists of color names used by British paint manufacturers and those used by the printing ink industry are included, set out in such a way that they can be readily compared with the colors reproduced in the Dictionary.
Thursday, February 08, 2007
Corundum Doublets
The most likely place to find doublets and triplets is in antique jewelry. It is also possible to find doublets and triplets in new pieces.
Assembled stones normally consist of two parts (doublets) or three parts (triplets) glued together for the following reasons:
- to provide a better wearing surface.
- to obtain a large stone from two smaller pieces of natural gem material.
- to provide better color and appearance.
The purpose of producing corundum doublet is to have the careless buyer look into the table of the stone, see the natural inclusions on the crown area, then purchase the gem at a high price. This deception is possible because of the thin crown of colorless or light yellowish green sapphire does not influence the color the stone face up (table-up), which is determined by the synthetic material on the pavilion. Few buyers actually check the girdle of the stone. Corundum doublets are easy to detect if the buyer is aware of their features. The careless buyer can easily be fooled.
When you are trying to identify an unknown stone always suspect an assembled stone. To avoid the mother-of-all surprise you should look for the difference in color, luster or inclusions, plane of join, gas bubbles (if any) between the crown and pavilion (base) of the gem material. Doublets consisting of black star sapphire on the crown and pavilion of lower quality natural sapphire is also common. There is also doublet made of a base of a black, non-transparent layer of natural star sapphire topped with synthetic orange sapphire or synthetic spinel (flame fusion). Use good lighting and proper magnification to view the color contrast so that you are able to identify the stone.
Assembled stones normally consist of two parts (doublets) or three parts (triplets) glued together for the following reasons:
- to provide a better wearing surface.
- to obtain a large stone from two smaller pieces of natural gem material.
- to provide better color and appearance.
The purpose of producing corundum doublet is to have the careless buyer look into the table of the stone, see the natural inclusions on the crown area, then purchase the gem at a high price. This deception is possible because of the thin crown of colorless or light yellowish green sapphire does not influence the color the stone face up (table-up), which is determined by the synthetic material on the pavilion. Few buyers actually check the girdle of the stone. Corundum doublets are easy to detect if the buyer is aware of their features. The careless buyer can easily be fooled.
When you are trying to identify an unknown stone always suspect an assembled stone. To avoid the mother-of-all surprise you should look for the difference in color, luster or inclusions, plane of join, gas bubbles (if any) between the crown and pavilion (base) of the gem material. Doublets consisting of black star sapphire on the crown and pavilion of lower quality natural sapphire is also common. There is also doublet made of a base of a black, non-transparent layer of natural star sapphire topped with synthetic orange sapphire or synthetic spinel (flame fusion). Use good lighting and proper magnification to view the color contrast so that you are able to identify the stone.
Forrest Gump Movie
A memorable quote from the movie:
Forrest Gump (Tom Hanks): My momma always said, "Life was like a box of chocolates. You never know what you're gonna get."
Forrest Gump (Tom Hanks): My momma always said, "Life was like a box of chocolates. You never know what you're gonna get."
The Federal Trade Commission’s Guide for the Jewelry, Precious Metals and Pewter Industries
FTC writes:
23.14 Misuse of the term "blue white."
It is unfair or deceptive to use the term "blue white" or any representation of similar meaning to describe any diamond that under normal, north daylight or its equivalent shows any color or any trace of any color other than blue or bluish.
More info @ http://www.ftc.gov/bcp/guides/jewel-gd.htm
23.14 Misuse of the term "blue white."
It is unfair or deceptive to use the term "blue white" or any representation of similar meaning to describe any diamond that under normal, north daylight or its equivalent shows any color or any trace of any color other than blue or bluish.
More info @ http://www.ftc.gov/bcp/guides/jewel-gd.htm
Emeralds Of Pakistan
By Ali H Kazmi and L W Snee
Geological Survey of Pakistan
Van Nostrand Reinhold Company
1989 ISBN 0-442-30328-9
Van Nostrand Reinhold Company writes:
Emerald has been known to mankind since prehistoric times and yet is one of the rarest of gemstones—found only in a few locations. The uniqueness of emerald is a result of the unusual combination of two chemical elements, beryllium and chromium, that normally are not associated in nature. This special combination is controlled by fascinating geological processes that brought rocks of very different character together under conditions that permitted the formation of these beautiful green gems. Thus, emerald is not only fascinating to the gemologist and mineral collector because of its exceptional beauty but also to the geologist because of the geological process it represents.
Emeralds of Pakistan—geology, gemology, and genesis examines emeralds of Pakistan from three viewpoints—geologic, occurrence, physical and chemical characteristics of the gems, and origin. With scores of figures, including 81 color plates, the book describes and illustrates emeralds of Pakistan and summarizes the geologic occurrence of other worldwide emerald deposits.
Nine chapters and a selected bibliography summarize nearly ten years of research by 12 scientists. Emeralds of Pakistan—geology, gemology, and genesis covers such topics as:
- geology and tectonics of Pakistan
- geologic setting of Pakistan emeralds
- gemological characteristics of Pakistani emeralds
- comprehensive data on inclusions within the emeralds
- chemistry of the emeralds and their host rocks
- microprobe analyses of the emeralds
- geology of world emerald deposits
- origin of emeralds
- selected bibliography
This is the first book of its kind on the geology of emerald deposits of one area in the world. However, the book also presents the best current summary of all world emerald deposits and develops a new classification system for emerald deposits.
Geological Survey of Pakistan
Van Nostrand Reinhold Company
1989 ISBN 0-442-30328-9
Van Nostrand Reinhold Company writes:
Emerald has been known to mankind since prehistoric times and yet is one of the rarest of gemstones—found only in a few locations. The uniqueness of emerald is a result of the unusual combination of two chemical elements, beryllium and chromium, that normally are not associated in nature. This special combination is controlled by fascinating geological processes that brought rocks of very different character together under conditions that permitted the formation of these beautiful green gems. Thus, emerald is not only fascinating to the gemologist and mineral collector because of its exceptional beauty but also to the geologist because of the geological process it represents.
Emeralds of Pakistan—geology, gemology, and genesis examines emeralds of Pakistan from three viewpoints—geologic, occurrence, physical and chemical characteristics of the gems, and origin. With scores of figures, including 81 color plates, the book describes and illustrates emeralds of Pakistan and summarizes the geologic occurrence of other worldwide emerald deposits.
Nine chapters and a selected bibliography summarize nearly ten years of research by 12 scientists. Emeralds of Pakistan—geology, gemology, and genesis covers such topics as:
- geology and tectonics of Pakistan
- geologic setting of Pakistan emeralds
- gemological characteristics of Pakistani emeralds
- comprehensive data on inclusions within the emeralds
- chemistry of the emeralds and their host rocks
- microprobe analyses of the emeralds
- geology of world emerald deposits
- origin of emeralds
- selected bibliography
This is the first book of its kind on the geology of emerald deposits of one area in the world. However, the book also presents the best current summary of all world emerald deposits and develops a new classification system for emerald deposits.
Wednesday, February 07, 2007
Diffusion Treatment Of Natural And Synthetic Sapphire And Ruby
Corundum with sufficient titanium are good samples for the development of asterism (stars) by heat treatment. Asterism can be developed by diffusing titanium into the corundum crystal lattice with appropriate heat treatment apparatus. The technique is very similar to the production of asterism in Verneuil (flame fusion)-grown synthetic sapphires without titanium content. The technique is applied by many companies to produce stones with asterism (stars). In Thailand both natural, synthetic and treated stones are available.
The process consists of :
1. Diffusion treatment of corundum samples in mixture of aluminum oxide and titanium oxide powder. The temperatures required to facilitate the process (diffusing a thin surface layer) may be in the range of 1700 - 1950 degrees centigrade.
2. The samples are then heat treated in a temperature in the range of 1100 - 1500 degrees centigrade permitting the formation of rutile needles in the surface layer.
The asterism (stars) created by this two step process is caused by needles within only a thin surface layer. When properly done, the visual appearance of treated samples may look very similar to that of untreated natural stones.
With careful examination under the microscope + immersion technique (with sample stones: treated + untreated stones) most treated stones can be identified if they are unset (loose stones).
The process consists of :
1. Diffusion treatment of corundum samples in mixture of aluminum oxide and titanium oxide powder. The temperatures required to facilitate the process (diffusing a thin surface layer) may be in the range of 1700 - 1950 degrees centigrade.
2. The samples are then heat treated in a temperature in the range of 1100 - 1500 degrees centigrade permitting the formation of rutile needles in the surface layer.
The asterism (stars) created by this two step process is caused by needles within only a thin surface layer. When properly done, the visual appearance of treated samples may look very similar to that of untreated natural stones.
With careful examination under the microscope + immersion technique (with sample stones: treated + untreated stones) most treated stones can be identified if they are unset (loose stones).
Sting Movie
Memorable quote (s) from the movie:
J.J. Singleton (Ray Walston): I dunno know what to do with this guy, Henry. He's an Irishman who doesn't drink, doesn't smoke, and doesn't chase dames. He's a grand knight in the Knights of Columbus, and he only goes out to play faro. Sometimes plays 15 or 20 hours at a time, just him against the house.
Henry Gondorff (Paul Newman): Roulette? Craps?
J.J. Singleton (Ray Walston): He won't touch them. The croupier at Gilman's says he never plays anything he can't win.
Henry Gondorff (Paul Newman): Sports?
J.J. Singleton (Ray Walston): Likes to be seen with fighters sometimes, but he doesn't go to the fights or bet on them.
Henry Gondorff (Paul Newman): Jesus. Does he do anything where he's not alone?
J.J. Singleton (Ray Walston): Just poker. And he cheats. Pretty good at it, too.
J.J. Singleton (Ray Walston): I dunno know what to do with this guy, Henry. He's an Irishman who doesn't drink, doesn't smoke, and doesn't chase dames. He's a grand knight in the Knights of Columbus, and he only goes out to play faro. Sometimes plays 15 or 20 hours at a time, just him against the house.
Henry Gondorff (Paul Newman): Roulette? Craps?
J.J. Singleton (Ray Walston): He won't touch them. The croupier at Gilman's says he never plays anything he can't win.
Henry Gondorff (Paul Newman): Sports?
J.J. Singleton (Ray Walston): Likes to be seen with fighters sometimes, but he doesn't go to the fights or bet on them.
Henry Gondorff (Paul Newman): Jesus. Does he do anything where he's not alone?
J.J. Singleton (Ray Walston): Just poker. And he cheats. Pretty good at it, too.
Charles T Munger
One of my favourite quote from Charles Munger.
Charles T Munger, Vice-Chairman of Berkshire Hathaway Corporation writes:
"Never wrestle with a pig, for if you do, you will both get dirty, but the pig will enjoy it."
Charles T Munger, Vice-Chairman of Berkshire Hathaway Corporation writes:
"Never wrestle with a pig, for if you do, you will both get dirty, but the pig will enjoy it."
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