(via The Canadian Gemmologist)
Significant strides have been made in the quality and availability of pocket sized LED applications for gemological applications. Conventional lighting is by no means obsolete in the study of gemology. But now with so many models from which to choose, pocket LED light sources certainly have their place.
Read on to learn more @
www.equipped.com/led_lights.htm
http://www.howstuffworks.com
http://www.led-lenser.com
http://www.leevalley.com
http://www.nichia.co.jp
http://www.photonlight.com
www.physics.ubc.ca/~outreach/phys420/p420_95/mark/htheory.html
http://www.scotgem.demon.co.uk
Contact Sources In Canada
Active Surplus, 347 Queen St. W., Toronto. 416-593-0909
-Electronic components, including diodes; Pocket laser pointers; Scientific glassware such as Petri dishes, beakers, etc.
Canadian Gemmological Association, 1767 Avenue Rd, Toronto. 416-785-0962
-Nebula LW UV pocket LED
Efstonscience, 3350 Dufferin St., Toronto. 1-800-777-5255 for mail order
-Electronic components, including colored diodes by special request; Laser pocket LEDs; LW UV pocket LED
Marathon Sports Ltd., 367 King St. W., Toronto. 416-593-5850
-A good selection of Photon®Microlights (LW UV by request)
Mountain Equipment Co-op, 400 King St. W., Toronto. 416-340-2667
-Photon®I Microlight only (white, blue, yellow, red)
Lee Valley Tools, various locations. 1-800-267-8767 for mail order in Canada.
-Photonpump®VI Moonlenser in white, blue and red; Flexible Neck Lamps in white, large and small models
Vistek, 496 Queens St. E., Toronto. 416-365-1777
- Lee Filters Series of photographic gels
Thursday, March 15, 2007
Contemporary Costume Jewelry
By Elyse Sommer
George Allen & Unwin Ltd
1974 ISBN 0-04730026-4
George Allen & Unwin writes:
For anyone who wants to create stunning and imaginative jewelry with a minimum of skill and expense, Elyse Sommer’s new book provides a wealth of inspiring ideas. Here, in a new look at an ancient craft, the author explores the infinite potential of jewelry making, revealing how a combination of unusual methods and materials can work for the artist to give fullest expression to his ideas. The beginner is launched into creative designing with some eye-opening suggestions for recycling antique store and flea market items such as ivory piano keys, crystal chandelier parts and brass stampings into charming and sophisticated jewelry worthy of the most elegant boutique.
The budding jeweler is told where to find and how to use the proper stringing materials and findings; drilling, sawing, bending, and finishing tools. A discussion of solderless methods, including a multimedia adhesive chart, completes this definitive chapter on tools and supplies. The author then goes on to introduce some of the most popular materials with which to create multimedia jewelry. She describes with the help of invaluable step-by-step photographs, the most common wire-working techniques, such as bending, twisting, looping, hammering, and wire crocheting. Demonstration projects range from a simple wire choker to beautiful necklaces and earrings of twisted wire and beads.
Metal jewelry examples include objects of copper, brass and silver being cut, pierced, shaped, filed, and inlaid to produce gorgeous body ornaments. The author shows why wood is such a versatile medium, lending itself to the creating of alluring pendants, brilliantly dyed beads, even combs and miniature sculptures to wear. Other media extensively discussed are glass, plastics, clay (firing and non-firing), fabrics, fibers, leather, paper, and natural materials.
Contemporary Costume Jewelry is the ideal book for all artists and craftsmen, experienced or not, who would like to fashion one-of-a-kind jewelry from simple materials. Whether it is a silver ring accented with a touch of tooled copper; a necklace made of felt patchwork, embroidered burlap or wrapped yarn; a watchcase made from a real eggshell; a bold and daring papier-mache necklace; or a pendant made from an old ivory mah-jongg tile, a host of exquisite creations await the follower of Elyse Sommer’s clear and easy-to-follow instructions.
George Allen & Unwin Ltd
1974 ISBN 0-04730026-4
George Allen & Unwin writes:
For anyone who wants to create stunning and imaginative jewelry with a minimum of skill and expense, Elyse Sommer’s new book provides a wealth of inspiring ideas. Here, in a new look at an ancient craft, the author explores the infinite potential of jewelry making, revealing how a combination of unusual methods and materials can work for the artist to give fullest expression to his ideas. The beginner is launched into creative designing with some eye-opening suggestions for recycling antique store and flea market items such as ivory piano keys, crystal chandelier parts and brass stampings into charming and sophisticated jewelry worthy of the most elegant boutique.
The budding jeweler is told where to find and how to use the proper stringing materials and findings; drilling, sawing, bending, and finishing tools. A discussion of solderless methods, including a multimedia adhesive chart, completes this definitive chapter on tools and supplies. The author then goes on to introduce some of the most popular materials with which to create multimedia jewelry. She describes with the help of invaluable step-by-step photographs, the most common wire-working techniques, such as bending, twisting, looping, hammering, and wire crocheting. Demonstration projects range from a simple wire choker to beautiful necklaces and earrings of twisted wire and beads.
Metal jewelry examples include objects of copper, brass and silver being cut, pierced, shaped, filed, and inlaid to produce gorgeous body ornaments. The author shows why wood is such a versatile medium, lending itself to the creating of alluring pendants, brilliantly dyed beads, even combs and miniature sculptures to wear. Other media extensively discussed are glass, plastics, clay (firing and non-firing), fabrics, fibers, leather, paper, and natural materials.
Contemporary Costume Jewelry is the ideal book for all artists and craftsmen, experienced or not, who would like to fashion one-of-a-kind jewelry from simple materials. Whether it is a silver ring accented with a touch of tooled copper; a necklace made of felt patchwork, embroidered burlap or wrapped yarn; a watchcase made from a real eggshell; a bold and daring papier-mache necklace; or a pendant made from an old ivory mah-jongg tile, a host of exquisite creations await the follower of Elyse Sommer’s clear and easy-to-follow instructions.
Wednesday, March 14, 2007
A History Told In Beads
Two Pakistani artisans explain and demonstrate the time and energy involved in their bead making. They can make copies of ancient beads with the same quality of the originals. This is good news, because this helps collectors get very good replicas without having to loot archaeological sites.
Read on to learn more @ http://www.lapidaryjournal.com/feature/299str.cfm
Read on to learn more @ http://www.lapidaryjournal.com/feature/299str.cfm
L.A. Confidential
Memorable quote (s) from the movie:
Sid Hudgens (Danny DeVito): Off the record, on the QT, and very hush-hush. Come to Los Angeles! The sun shines bright, the beaches are wide and inviting, and the orange groves stretch as far as the eye can see. There are jobs aplenty, and land is cheap. Every working man can have his own house, and inside every house, a happy, all-American family. You can have all this, and who knows... you could even be discovered, become a movie star... or at least see one. Life is good in Los Angeles... it's paradise on Earth." Ha ha ha ha. That's what they tell you, anyway.
Sid Hudgens (Danny DeVito): Off the record, on the QT, and very hush-hush. Come to Los Angeles! The sun shines bright, the beaches are wide and inviting, and the orange groves stretch as far as the eye can see. There are jobs aplenty, and land is cheap. Every working man can have his own house, and inside every house, a happy, all-American family. You can have all this, and who knows... you could even be discovered, become a movie star... or at least see one. Life is good in Los Angeles... it's paradise on Earth." Ha ha ha ha. That's what they tell you, anyway.
Race To The Bottom
A veteran Australian prospector and onetime dotcom entrepreneur is planning to scoop precious metals from the bottom of the ocean. He believes that it’s also the solution to all the ills that land-based mining has caused.
Read on to learn more @ http://www.wired.com/wired/archive/15.03/undersea.html
Read on to learn more @ http://www.wired.com/wired/archive/15.03/undersea.html
Jewelry By Architects
By Barbara Radice
Rizzoli International Publications, Inc
1987 ISBN 0-8478-0798-3
Barbara Radice writes:
The pieces of jewelry presented in this book have been designed from Cleto Munari by sixteen architects from all over the world during a span of four years. Munari has been promoting works of design for more than ten years. His curriculum vitae, from his debut with the gold and silver cutlery designed by Carlo Scarpa to the present day, has maintained his reputation as an adventurous entrepreneur.
The jewelry project began almost by chance in 1982 when Munari asked Michele De Lucchi to design a ring for his wife Valentina, and soon after made a similar request of Sottsass. Enchanted with the first designs and prototypes, Munari became more and more enthusiastically involved in assembling an increasingly international collection, to the point of setting up a small company to employ goldsmiths with the exclusive task of producing the pieces by hand as they were designed by various architects. Today the collection comprises over one hundred fifty pieces and, quite apart from its worth in gold, gems, and craftsmanship, it cost in patience, dedication, and astuteness, indispensable skills when it came not only to dealing with extremely busy architects but also to convincing them to divert their talents from their customary obsession and devote them to secondary activities.
When talking of very famous architects, no more than about thirty names are likely to be raised. They are the same names that come up again and again on the panels of international shows and competitions, the same who exchange polite criticisms and views in the pages of newspapers. They are the beloved protagonists of the great architectural telenovela incessantly fueled by corporate and society gossip broadcast by magazines and reviews and echoed by students, intellectuals, and pursuers of celebrities.
There is no cultural event of significance that can do without their very special presence, support, or advice. Their success as a category is perhaps due to the fact that they are forced by circumstances to be at the same time artists, intellectuals, businessmen, and managers. They are not always able to pull this off but it does make them into the most complex, protean Renaissance figures in the whole professional scene.
Big architects are often progressive intellectuals; even those regarded as more conservative always manage to cultivate some fad or snobbism that sets them apart. In general, they are better dressed than artists, travel a great deal and are always calling each other on the phone. When they are not talking about the financial problems which eternally afflict them or about work, they know how to have a good time and are open to adventure. They can be recognized by a special quality in their gaze, conveying an amused, cynical detachment, and by the sly smile of those who possess secret information.
The fifteen architects (Peter Shire is a designer) who have designed jewelry for Cleto Munari are all renowned; many of them are real superstars. It is no coincidence that the collection is a rather extraordinary event. It represents the debut of postmodernism in the jeweler’s craft, or, if you like, the first true figurative modernization of jewelry design as an applied art since the twenties and thirties. The creative exploits of artists like Calder or Picasso, Man Ray, De Chirico, Braque, Dali, Fontana or Stella in this field have never succeeded in creating a new trend in the design of jewelry or to alter its figurative canons in the way that the historical avante-garde movements did at the beginning of the century.
Like all postmodern phenomena, the collection, made up of figurative and abstract pieces that are architectonic, symbolic, or ritual to varying degrees, is figuratively heterogeneous but homogeneous in its intellectual approach to the theme, in the eclecticism of the solutions and in the curious uniformity of the materials used: almost exclusively yellow gold and semi-precious stones, apart from the odd ironical touch provided by some synthetic gemstone or slab of small brilliants used as a luminous plane in the combination with other volumes.
The spurning of precious stones, already given a clear thumbs down by the masters of Art Deco, is a rejection of the status symbol based on cost and a reaffirmation of the superior power and value of the design over that of gems, as was the case during the Renaissance.
The architects have designed their jewelry as a formal exercise, as an extension of their work with architecture. They have conceived them as purely decorative objects or as talismans charged with symbolic meaning. Perhaps the most fascinating thing about these one hundred and fifty odd pieces of jewelry is that they have nothing to do with any other set of jewelry designed over the last two thousand years. On the other hand they have an affinity with, if not a real resemblance to, other much more ancient examples of jewelry, such as Sumerian or Minoan, or primitive ornaments from Africa or Melanesia. They draw on the most distant past, a past that is mysterious because it is forgotten. They do not repeat styles but seek out ritual cadences, concealed fragilities, tenuous figurative suggestions, or powerful and solemn forms.
They are very moving objects, serious, intense, even nostalgic. Whatever their origin or inspiration, they translate into gold the most advanced figurative research of the last twenty years.
About the author
Barbara Radice is the author of Memphis, published by Rizzoli in 1984.
Rizzoli International Publications, Inc
1987 ISBN 0-8478-0798-3
Barbara Radice writes:
The pieces of jewelry presented in this book have been designed from Cleto Munari by sixteen architects from all over the world during a span of four years. Munari has been promoting works of design for more than ten years. His curriculum vitae, from his debut with the gold and silver cutlery designed by Carlo Scarpa to the present day, has maintained his reputation as an adventurous entrepreneur.
The jewelry project began almost by chance in 1982 when Munari asked Michele De Lucchi to design a ring for his wife Valentina, and soon after made a similar request of Sottsass. Enchanted with the first designs and prototypes, Munari became more and more enthusiastically involved in assembling an increasingly international collection, to the point of setting up a small company to employ goldsmiths with the exclusive task of producing the pieces by hand as they were designed by various architects. Today the collection comprises over one hundred fifty pieces and, quite apart from its worth in gold, gems, and craftsmanship, it cost in patience, dedication, and astuteness, indispensable skills when it came not only to dealing with extremely busy architects but also to convincing them to divert their talents from their customary obsession and devote them to secondary activities.
When talking of very famous architects, no more than about thirty names are likely to be raised. They are the same names that come up again and again on the panels of international shows and competitions, the same who exchange polite criticisms and views in the pages of newspapers. They are the beloved protagonists of the great architectural telenovela incessantly fueled by corporate and society gossip broadcast by magazines and reviews and echoed by students, intellectuals, and pursuers of celebrities.
There is no cultural event of significance that can do without their very special presence, support, or advice. Their success as a category is perhaps due to the fact that they are forced by circumstances to be at the same time artists, intellectuals, businessmen, and managers. They are not always able to pull this off but it does make them into the most complex, protean Renaissance figures in the whole professional scene.
Big architects are often progressive intellectuals; even those regarded as more conservative always manage to cultivate some fad or snobbism that sets them apart. In general, they are better dressed than artists, travel a great deal and are always calling each other on the phone. When they are not talking about the financial problems which eternally afflict them or about work, they know how to have a good time and are open to adventure. They can be recognized by a special quality in their gaze, conveying an amused, cynical detachment, and by the sly smile of those who possess secret information.
The fifteen architects (Peter Shire is a designer) who have designed jewelry for Cleto Munari are all renowned; many of them are real superstars. It is no coincidence that the collection is a rather extraordinary event. It represents the debut of postmodernism in the jeweler’s craft, or, if you like, the first true figurative modernization of jewelry design as an applied art since the twenties and thirties. The creative exploits of artists like Calder or Picasso, Man Ray, De Chirico, Braque, Dali, Fontana or Stella in this field have never succeeded in creating a new trend in the design of jewelry or to alter its figurative canons in the way that the historical avante-garde movements did at the beginning of the century.
Like all postmodern phenomena, the collection, made up of figurative and abstract pieces that are architectonic, symbolic, or ritual to varying degrees, is figuratively heterogeneous but homogeneous in its intellectual approach to the theme, in the eclecticism of the solutions and in the curious uniformity of the materials used: almost exclusively yellow gold and semi-precious stones, apart from the odd ironical touch provided by some synthetic gemstone or slab of small brilliants used as a luminous plane in the combination with other volumes.
The spurning of precious stones, already given a clear thumbs down by the masters of Art Deco, is a rejection of the status symbol based on cost and a reaffirmation of the superior power and value of the design over that of gems, as was the case during the Renaissance.
The architects have designed their jewelry as a formal exercise, as an extension of their work with architecture. They have conceived them as purely decorative objects or as talismans charged with symbolic meaning. Perhaps the most fascinating thing about these one hundred and fifty odd pieces of jewelry is that they have nothing to do with any other set of jewelry designed over the last two thousand years. On the other hand they have an affinity with, if not a real resemblance to, other much more ancient examples of jewelry, such as Sumerian or Minoan, or primitive ornaments from Africa or Melanesia. They draw on the most distant past, a past that is mysterious because it is forgotten. They do not repeat styles but seek out ritual cadences, concealed fragilities, tenuous figurative suggestions, or powerful and solemn forms.
They are very moving objects, serious, intense, even nostalgic. Whatever their origin or inspiration, they translate into gold the most advanced figurative research of the last twenty years.
About the author
Barbara Radice is the author of Memphis, published by Rizzoli in 1984.
Tuesday, March 13, 2007
Reinventing The Wheel: The OMF Concave Factor
(via Lapidary Journal, November 1997) Andy Oriel writes:
The story of the concave faceting machine is a revolutionary one—which could be said about any machine that revolves on several axes. But in the case of the OMF faceters, which stands for optically magnified facets, the description is justified.
Developed about 10 (20) years ago by Dough Hoffman of Polymetric Instruments, the machine is capable of cutting both concave and convex facets. Instead of grinding a stone against a flat lap as in conventional faceting, concave facets are ground against rotating copper and plastic cylinders of varying diameters, which are charged with abrasive compounds and move forward and back to prevent grooving.
“There are two main benefits to concave faceting,” says gem artists Mark Gronlund, slipping into teaching mode. “The first is the ability to cut new and unusual shapes. With flat facets you’re limited to shapes like rounds, ovals, marquise, and emeralds. But with the combination of flat and concave faceting, there are almost no limitations to shapes or girdle outlines.
“The second benefit,” he explains, “is an increase in the brilliance of a stone.” In a conventional stone, when light enters through the table and hit a pavilion facet, it is reflected in only one direction. By contrast, with a concave pavilion, which from the top of the stone appears as a convex surface, the light is scattered in many directions.
“Basically what we are doing is putting a bunch of magnifiers and diffusers into a stone, like little eyeglass lenses,” he says. “The convex surfaces focus light and the concave surfaces diffuse it.”
“Flat faceting is a three-step process with a rough cut, a final cut, and then polishing. With concave faceting, you still have to lay in all the flat faces first—the same first two steps. But then you transfer the interchangeable mast from the faceting machine to the OMF for an additional three to sometimes six more steps.”
If it sounds complex, it is. Suffice it to say that concave cut stones are several magnitudes brighter than normal, as if fire works were going off inside them; they appear to have many more facets than they actually have; and they tend to look slightly darker than otherwise, all of which have thrown the traditional colored stone industry a curve ball.
Less valuable stones, such as citrines and light aquamarines, are transformed from bridesmaid into blushing brides. A happy side effect of the phenomenon is that a cutter’s budget for rough is considerably stretched. And from the buyer’s point of view, large, precision-cut stones can be purchased for the price of mediocre, more traditionally precious ones.
There are imitations, however. Already dark stones, such as garnets and sapphires, tend not to benefit from the treatment. And small stones tend to become overly busy-looking like gliding a lily.
The story of the concave faceting machine is a revolutionary one—which could be said about any machine that revolves on several axes. But in the case of the OMF faceters, which stands for optically magnified facets, the description is justified.
Developed about 10 (20) years ago by Dough Hoffman of Polymetric Instruments, the machine is capable of cutting both concave and convex facets. Instead of grinding a stone against a flat lap as in conventional faceting, concave facets are ground against rotating copper and plastic cylinders of varying diameters, which are charged with abrasive compounds and move forward and back to prevent grooving.
“There are two main benefits to concave faceting,” says gem artists Mark Gronlund, slipping into teaching mode. “The first is the ability to cut new and unusual shapes. With flat facets you’re limited to shapes like rounds, ovals, marquise, and emeralds. But with the combination of flat and concave faceting, there are almost no limitations to shapes or girdle outlines.
“The second benefit,” he explains, “is an increase in the brilliance of a stone.” In a conventional stone, when light enters through the table and hit a pavilion facet, it is reflected in only one direction. By contrast, with a concave pavilion, which from the top of the stone appears as a convex surface, the light is scattered in many directions.
“Basically what we are doing is putting a bunch of magnifiers and diffusers into a stone, like little eyeglass lenses,” he says. “The convex surfaces focus light and the concave surfaces diffuse it.”
“Flat faceting is a three-step process with a rough cut, a final cut, and then polishing. With concave faceting, you still have to lay in all the flat faces first—the same first two steps. But then you transfer the interchangeable mast from the faceting machine to the OMF for an additional three to sometimes six more steps.”
If it sounds complex, it is. Suffice it to say that concave cut stones are several magnitudes brighter than normal, as if fire works were going off inside them; they appear to have many more facets than they actually have; and they tend to look slightly darker than otherwise, all of which have thrown the traditional colored stone industry a curve ball.
Less valuable stones, such as citrines and light aquamarines, are transformed from bridesmaid into blushing brides. A happy side effect of the phenomenon is that a cutter’s budget for rough is considerably stretched. And from the buyer’s point of view, large, precision-cut stones can be purchased for the price of mediocre, more traditionally precious ones.
There are imitations, however. Already dark stones, such as garnets and sapphires, tend not to benefit from the treatment. And small stones tend to become overly busy-looking like gliding a lily.
Gigi
Memorable quote (s) from the movie:
Gigi (Leslie Caron): Who gave it to you, Aunt?
Aunt Alicia (Isabel Jeans): A King
Gigi (Leslie Caron): A great king?
Aunt Alicia (Isabel Jeans): No, a little one. Great kings do not give very large stones.
Gigi (Leslie Caron): Why not?
Aunt Alicia (Isabel Jeans): In my opinion it's because they don't feel they have to.
Gigi (Leslie Caron): Well, who does give the valuable jewels?
Aunt Alicia (Isabel Jeans): Who? Oh the shy, the proud, and the social climbers because they think it's a sign of culture; But it doesn't matter who gives them, as long as you never wear anything second rate. Wait for the first class jewels Gigi. Hold on to your ideals.
Gigi (Leslie Caron): Who gave it to you, Aunt?
Aunt Alicia (Isabel Jeans): A King
Gigi (Leslie Caron): A great king?
Aunt Alicia (Isabel Jeans): No, a little one. Great kings do not give very large stones.
Gigi (Leslie Caron): Why not?
Aunt Alicia (Isabel Jeans): In my opinion it's because they don't feel they have to.
Gigi (Leslie Caron): Well, who does give the valuable jewels?
Aunt Alicia (Isabel Jeans): Who? Oh the shy, the proud, and the social climbers because they think it's a sign of culture; But it doesn't matter who gives them, as long as you never wear anything second rate. Wait for the first class jewels Gigi. Hold on to your ideals.
The Truth About Gemstone Smuggling
Gem smuggling requires patience, knowledge of local and international customs and traditions, special skills to locate the source and find local and international buyers, the ability to collect money on time so that you are able to continue your ‘creative’ trading practices for a living. Some may do it for fun, but most transactions are serious businesses. Law enforcement agencies around the world may care about gem smuggling when it is linked to terrorism, money laundering, drug smuggling or organized crime. Smuggled gems are sometimes discovered in connection to one of these activities, but gem smuggling by itself is a relatively low priority. The situation is compounded because of the inability to ascertain the origin of stones.
Read on to learn more @ http://www.colored-stone.com/stories/jul04/smuggling.cfm
Read on to learn more @ http://www.colored-stone.com/stories/jul04/smuggling.cfm
Turquoise: The Gem Of The Centuries
By Oscar T Branson
Treasure Chest Publications, Inc
1975
Oscar T Branson writes:
There is a haunting fascination to turquoise, a feeling that takes hold of a person who comes in contact with it for a time. This fascination has been the same down through the centuries and its popularity has spread through many countries of the world. The Egyptians some 70 centuries ago were captivated by it. The evidence is a bracelet of carved turquoise and gold found on the mummified arm of an Egyptian queen. This is the oldest known example of jewelry and was made over seven thousand years ago. For the next several thousand years the Pharaohs sent expeditions of hundreds of men into the Sinai Desert to mine this coveted stone. It was used in almost every decorative way imaginable from beads in jewelry to the lavish decoration of sarcophagi. The Egyptian tombs with their hoards of gold were too great a temptation to looters and thieves and consequently there is pitifully little left for us to see.
In Persia the earliest mention of turquoise is in a story about the mine of Isaac, the father of Israel, who lived about 2100 B.C. Turquoise has been mined in Persia since before that time. It was used as lavishly in Persia as it was in Egypt. Persian writings tell of large vases carved from huge pieces of turquoise. One of the largest had the capacity of six gallons.
The origin of the use of turquoise in Tibet is thought to be very early as the Tibetan word for it is original and not borrowed from another language, as it has been in most languages. Practically everyone in Tibet has a love for turquoise; in fact this fascination almost amounts to a mania.
In China turquoise was used in very early times and much has always been worn in jewelry. Large quantities were made into beads and traded into Mongolia, Tibet and other countries. This is also done today. Due to the occurrence in China of large pieces of turquoise of carving quality, the stone gained an ornamental status. Many carvings of large size are known and some are still being made. The Chinese are greatly fascinated by turquoise, and to them it is second only to jade.
In our own Southwest, turquoise mines were worked by Indians before the time of Christ. In fact many of the mines that are producing today were worked in prehistoric times. Here in America today thousands of people are becoming aware of it and the old fascination is taking hold. Down through the ages and especially now, fine gems and jewelry have been a commodity more stable than money. In other words it is and always has been a good investment. Turquoise and silver jewelry is a pleasure to wear and enjoy. While one is enjoying it, they are aware that is something of value, both intrinsic and esthetic.
Some people think turquoise is a fad. If this is so, it has been a fad for over 7000 years.
Treasure Chest Publications, Inc
1975
Oscar T Branson writes:
There is a haunting fascination to turquoise, a feeling that takes hold of a person who comes in contact with it for a time. This fascination has been the same down through the centuries and its popularity has spread through many countries of the world. The Egyptians some 70 centuries ago were captivated by it. The evidence is a bracelet of carved turquoise and gold found on the mummified arm of an Egyptian queen. This is the oldest known example of jewelry and was made over seven thousand years ago. For the next several thousand years the Pharaohs sent expeditions of hundreds of men into the Sinai Desert to mine this coveted stone. It was used in almost every decorative way imaginable from beads in jewelry to the lavish decoration of sarcophagi. The Egyptian tombs with their hoards of gold were too great a temptation to looters and thieves and consequently there is pitifully little left for us to see.
In Persia the earliest mention of turquoise is in a story about the mine of Isaac, the father of Israel, who lived about 2100 B.C. Turquoise has been mined in Persia since before that time. It was used as lavishly in Persia as it was in Egypt. Persian writings tell of large vases carved from huge pieces of turquoise. One of the largest had the capacity of six gallons.
The origin of the use of turquoise in Tibet is thought to be very early as the Tibetan word for it is original and not borrowed from another language, as it has been in most languages. Practically everyone in Tibet has a love for turquoise; in fact this fascination almost amounts to a mania.
In China turquoise was used in very early times and much has always been worn in jewelry. Large quantities were made into beads and traded into Mongolia, Tibet and other countries. This is also done today. Due to the occurrence in China of large pieces of turquoise of carving quality, the stone gained an ornamental status. Many carvings of large size are known and some are still being made. The Chinese are greatly fascinated by turquoise, and to them it is second only to jade.
In our own Southwest, turquoise mines were worked by Indians before the time of Christ. In fact many of the mines that are producing today were worked in prehistoric times. Here in America today thousands of people are becoming aware of it and the old fascination is taking hold. Down through the ages and especially now, fine gems and jewelry have been a commodity more stable than money. In other words it is and always has been a good investment. Turquoise and silver jewelry is a pleasure to wear and enjoy. While one is enjoying it, they are aware that is something of value, both intrinsic and esthetic.
Some people think turquoise is a fad. If this is so, it has been a fad for over 7000 years.
The Truth About Gemstone Smuggling
Gem smuggling requires patience, knowledge of local and international customs and traditions, special skills to locate the source and find local and international buyers, the ability to collect money on time so that you are able to continue your ‘creative’ trading practices for a living. Some may do it for fun, but most transactions are serious businesses. Law enforcement agencies around the world may care about gem smuggling when it is linked to terrorism, money laundering, drug smuggling or organized crime. Smuggled gems are sometimes discovered in connection to one of these activities, but gem smuggling by itself is a relatively low priority. The situation is compounded because of the inability to ascertain the origin of stones.
Read on to learn more @ http://www.colored-stone.com/stories/jul04/smuggling.cfm
Read on to learn more @ http://www.colored-stone.com/stories/jul04/smuggling.cfm
Monday, March 12, 2007
Looking One Use For Those Old CDs?
(via November 2001 Colorado Springs’ “Pick & Pack”, volume 41, number 9) Lapidary Journal writes:
Try using them for the final polish on your faceting machine. Rinse with water and a little detergent, then place it on top of the last cutting wheel. Center it reasonably well, as the hole is slightly larger than the shaft; then clamp it down. Spray the surface with 14000-grit diamond polishing compound; the charged CD should polish several stones.
Try using them for the final polish on your faceting machine. Rinse with water and a little detergent, then place it on top of the last cutting wheel. Center it reasonably well, as the hole is slightly larger than the shaft; then clamp it down. Spray the surface with 14000-grit diamond polishing compound; the charged CD should polish several stones.
Magnolia
Memorable quote (s) from the movie:
Narrator (Ricky Jay): And there is the account of the hanging of three men, and a scuba diver, and a suicide. There are stories of coincidence and chance, and intersections and strange things told, and which is which and who only knows? And we generally say, "Well, if that was in a movie, I wouldn't believe it." Someone's so-and-so met someone else's so-and-so and so on. And it is in the humble opinion of this narrator that strange things happen all the time. And so it goes, and so it goes. And the book says, "We may be through with the past, but the past ain't through with us."
Narrator (Ricky Jay): And there is the account of the hanging of three men, and a scuba diver, and a suicide. There are stories of coincidence and chance, and intersections and strange things told, and which is which and who only knows? And we generally say, "Well, if that was in a movie, I wouldn't believe it." Someone's so-and-so met someone else's so-and-so and so on. And it is in the humble opinion of this narrator that strange things happen all the time. And so it goes, and so it goes. And the book says, "We may be through with the past, but the past ain't through with us."
Buying Gemstones In Brazil
The article highlights the perils of buying colored gemstones in Brazil. People who visit Brazil buy colored gemstones with or without product knowledge. In all gem producing countries in the world, glass and synthetic corundum are the two most frequently encountered fakes. Even experts get taken for a ride because the fakes look so good. Sometimes we are distracted by other events when buying gemstones and become victims of ‘momentary autism’.
Read on to learn more……
(via The Canadian Gemmologist, Volume XII, Number 1, Spring 1991)
Some Fake Gems On The Brazilian Market And How To Identify Them
Joachim Karfunkel, Reinhard R Wenger, Wolney Lobato writes:
Abstract
After 15 years experience in the Brazilian gem market, the authors suggest a simple ‘micro-lab’ for the detection of imitations and falsifications. Descriptions of some of the most common fakes in cut stones, rough material, and specimens for collectors are given. Simple means for distinguishing them from genuine pieces are discussed.
Introduction
Brazil, a paradise on earth for gems, is also a territory with one of the highest incidences of gem and mineral falsifications. The story of imitations or fakes in gemology is probably as old as the first uses of minerals and similar materials for personal adornment. Webster (1983) writes: “It is, however, faience, a glazed siliceous ware made in Egypt as long ago as pre-dynastic times (before 4777 B.C) which is the more important as a beginning of imitation gemstones.”
We can define imitation as any substance used as a substitute for natural gem that fails to duplicate its composition, structure, and properties. Imitations aim to replace a gem with another cheaper material, which has a similar appearance, but different physical and chemical properties. Those imitations which have the purpose of misleading are called falsifications or fakes. To this group we could also add gems that have been treated to enhance their appearance, and supposed value, but which fade or change with time. Knowledge of these treatments should not be withheld from buyers. Further information on synthetics and gemstone enhancement can be found in Nassau, 1980, 1984.
The market for imitations in Brazil is huge, since most people there can’t afford to buy genuine gemstones. Similarly a metal other than gold is frequently used for settings. Imitations may be sold as genuine, and some regard the Brazilian market as a ‘cheating’ market. We want to emphasize that most of the Brazilian stone dealers are honest. Those few who want to mislead, however, sell their wares to everybody, including friends and even relatives! The problem is increased by lack of gemological education. The basic equipment is the human eye, sometimes aided with tweezers and a loupe. Most of those who possess a polariscope, dichroscope, refractometer, or microscope, usually don’t know how to use them. They sell the stones they bought believing truly that the stones are genuine.
The Micro-Lab
Many tourists, gem dealers and collectors prefer to buy in the interior of Brazil, rather than in the capitals like Belo Horizonte, Rio de Janeiro, Sao Paulo, Salvador, Fortaleza, or Porto Alegre. Obviously, it is very difficult to travel with a complete laboratory. We do not wish to imply that sophisticated equipment like refractometers, microscopes or spectroscopes is not important, but the tourist or collector often can’t afford such things, nor is it always possible to carry them in the field. Instead, we suggest a simple, cheap ‘micro-lab’ consisting of tweezers, loupe, polariscope, heavy liquid, and a hardness scale. Simple equipment can be effective when you understand how to use it.
Commercial polariscopes are usually expensive—why not build your own? Just buy a piece of Polaroid plastic and cut it into pieces about 2” square. Make a small stand (out of any kind of transparent, firm plastic), and glue the polaroid pieces on each side with the vibration directions perpendicular to each other. This polariscope may be used in the same manner as a conventional one. Place a light source (bulb, sunlight or torch) as near as possible to the polariscope. Hold the stone (rough or cut) between the filters with a hand or tweezers; rotate the stone, the polariscope or both, and observe the behavior (isotropic or anisotropic).
Heavy liquids are generally not cheap, but bromoform with a specific gravity of 2.83 at 15ºC can be acquired at relatively low cost. It should be emphasized that bromoform is a toxic substance, to be used only in a well ventilated area. Some practice is required to accurately estimate specific gravity, but the test is quick and even small stones (less than 0.5ct) may be measured accurately. The best method is by comparison: compare the rate of rise or fall of the unknown stone with that of a known one (indicator), possibly one of the specimens in the hardness scale. For example, the specific gravity of quartz is 2.65; beryl 2.7; pink tourmaline 2.05; fluorite 3.18; topaz 3.5; corundum 4.0.
You don’t need to buy a specimen for every number of hardness on the Moh’s scale. Small pieces of corundum (9), colorless topaz (8), quartz (7), feldspar (6), and apatite (5) will provide sufficient range of hardness and density. A piece of window glass, and a pocket knife are also practical. A piece of porcelain is useful to observe streak.
It may also be useful to have an ultraviolet lamp with short and long wave wavelength capabilities to detect adhesive on repaired or constructed specimens. Such a micro-lab is inexpensive and easy to carry.
Types of fakes
As the instances of fakes on the gem market are many, we can describe only a few and how they can be recognized. Imitations and fakes can be divided into three categories: cut stones, rough gem material and specimens for mineral collectors.
Fake faceted stones
Let’s look at the first group, cut and polished stones. You are probably not going to buy a Colombian emerald, an Indian spinel, or a Burma ruby in Brazil. The most common gems on the Brazilian market are topaz (blue and imperial), aquamarine, emerald, tourmaline, chrysoberyl (including cat’s eye and alexandrite), garnet (almandine and spessartine), amethyst, citrine, smoky and rose quartz, chrysoprase, agate, spodumene (variety kunzite), andalusite, sodalite, amazonite, hematite, etc. Less common are yellow beryl (heliodor), pink beryl (morganite), opal, green spodumene (hiddenite), fluorite, cordierite (iolite), kyanite, rhodochrosite, rhodonite, and apatite. More unusual gems like gahnite, petalite, scapolite, phenakite, amblygonite, brazilianite, titanite (sphene), diopside, euclase, etc and diamond will not be considered here.
On the gem market in Europe or the USA, you can find ‘well done’ imitations, sometimes difficult to detect without considerable gemological knowledge and equipment. In Brazil, however, cheap and readily available imitations such as glass, synthetic spinel, and synthetic corundum (both made by the Verneuil method) are common. Rarer are synthetic amethyst (hydrothermal), synthetic emerald (like Gilson and Chatham), synthetic corundum with a color change (Verneuil, alexandrite imitation) etc. Having a closer look at the Brazilian gems, we note that most of them are anisotropic except for garnet, which is isotropic, and agate and chrysoprase, which are cryptocrystalline varieties of quartz with a different behavior under the polariscope. The remaining opal, glass and synthetic spinel are opticall isotropic (with some anomalies). Knowing how to use the loupe and polariscope correctly, you can’t mistake these for one of the above listed gems. Almost all glasses on the Brazilian market have an S.G in the 2.52 region, and will float in bromoform. Most have an R.I around 1.52. An exception, dark violet in color, had S.G 3.18 and R.I 1.618; it sank slowly in bromoform. Don’t forget to use the loupe to look for bubbles and color distribution.
Most of the less common gems are also anisotropic, except opal (compare behavior in the literature) and fluorite. Many faceted violet fluorites were sold as amethyst in Belo Horizonte in 1986. This falsification is easily detected since fluorite is isotropic, and heavier than bromoform (3.18). Amethyst with an S.G of 2.65 floats, and is isotropic. It is much harder too, but hardness tests should not be carried out on a cut stone because they might cause damage.
Unfortunately synthetic emerald, synthetic corundum and synthetic alexandrite are not as easily distinguished from the genuine with the micro-lab, and require better equipment, including a microscope. Don’t buy ‘almost’ flawless stones with an excellent color without consulting a gemologist.
Characteristics of some glasses used as imitations
All the glasses were used to imitate gems of similar color.
Color: Violet; S.G = 2.52; R.I = 1.519; Optics = SR; 10x = Bubbles; Trace elements = Sr, Zr, Ba, La, Ce
Color: Honey yellow; S.G = 2.52; R.I = 1.518; Optics = SR; 10x = Bubbles; Trace elements = Pb, Sr, Ba, Zr
Color: Dark violet; S.G = 3.18; R.I = 1.618; Optics = SR; 10x = - ; Trace elements = Fe
Color: Medium blue; S.G = 2.52; R.I = 1.520; Optics = SR/ADR; 10x = Bubbles; Trace elements = Sr, Zr, Ba
Color: Dark blue; S.G = 2.52; R.I = 1.520; Optics = SR; 10x = - ; Trace elements = Sr, As, Sb
Color: Red yellow; S.G = 2.52; R.I = 1.518; Optics = SR; 10x = Bubbles; Trace elements = As, Se, Zr, Ba, Nd
Color: Green blue; S.G = 2.52; R.I = 1.518; Optics = SR; 10x = - ; Trace elements = Sr, Zr, Sn, Ba
Color: Emerald green; S.G = 2.52; R.I = 1.518; Optics = SR/ADR; 10x = Bubbles; Trace elements = Sr, Zr, Ba
Color: Light blue; S.G = 2.52; R.I = 1.519; Optics = SR; 10x = Bubbles; Trace elements = Sb, Zr, Sr, Ba
Note: The physical and optical properties were determined with an Eickorst refractometer, a Mettler scale, a GIA polariscope, a mineral light with short and long ultraviolet wavelengths, and Zeiss hand loupe 10x. The chemical analyses were kindly provided by Prof C Murtha and Prof R Murta (Nuclebras—Belo Horizonte) using x-ray energy spectrometry (detection limits for the above elements are 100ppm. All specimens are non-fluorescent in ultraviolet light except the red yellow glass, which weakly fluoresced a pale white in short wave UV)
Emeralds from the locality of Santa Terezinha, Goias, and those from Carnaiba/Socoto in Bahia usually have small black inclusions not seen in the synthetics (Gilson/Chatham). Only a few emeralds, some from the localities of Itabira and Nova Era, Minas Gerais, are ‘almost’ without inclusions. The prices are relatively high. So if you are offered such stones for US$200-300 per carat (one carat and larger), you can be sure that you have a synthetic in your hand.
Although corundum exists in Brazil (e.g ruby from Bahia and sapphire from Mato Grosso), the quality is very poor and usually not facetable. What generally appears on the market are Verneuil synthetic ruby and sapphire. Imitation alexandrites are frequently synthetic corundum with color change and not synthetic alexandrite. Synthetic stones of excellent quality, especially in old rings of 18 karat gold, are typically very poorly cut, and sometimes looked crooked. The old rule, ‘excellent gems have a very good cut, whereas low quality gems are poorly cut’ can be applied in this case. In larger stones, characteristic curved growth lines may be seen with the 10x loupe. Many of these stones, especially ruby, shows a very bright fluorescence with both long and short wave ultraviolet light.
Some fakes are so unexpected and simple that many buyers fail to recognize them because they don’t examine things carefully. For example, in the State of Ceara, northeast Brazil, a type of wax made from coconut (cera Carnauba) together with ink from a simple ballpoint pen is applied to white opal. The ink penetrates the opal and darkens it to simulate black opal. Examination with a 10x loupe will show concentration of the dark bluish ink along tiny crevices at the surface.
Falsifications of cat’s eye chrysoberyl may be made by irradiating asteriated quartz cabochons showing unusual strength of one of the rays. The color of the stone will turn brownish yellow, showing one strong ray only, thus imitating cat’s eye. A close look in different directions will reveal the asterism. If you are still in doubt, use the bromoform; chrysoberyl will sink whereas quartz will float.
Falsification of rough gem material
The second group, gem rough, is the easiest to detect, and there are only a few fakes on the market. Glass is commonly used to imitate tourmaline and aquamarine. In the case of tourmaline, green to bluish green glass has been fashioned into prismatic ‘crystals’ and even grooved with a saw to simulate the striations on a natural crystal. Upon magnification, these ‘striations’ appear to too regular. Other fake tourmalines are bicolored (e.g green and blue, green and red, or bright green and olive green) and often have inclusions (impurities). These are made from toy ‘marbles’, small glass spheres. Real tourmaline appears dark to almost black in the direction of the crystallographic axis (its optic axis); these will not. With the loupe it may be possible to detect bubbles in the glass and swirls of color. If there is still doubt, use the polariscope (not in the direction of the optic axis) or the bromoform. Bromoform will not distinguish between common glass and aquamarine, as both float, but tourmaline will sink. The polariscope will leave you without doubt.
Another fake on the market, already mentioned, is violet fluorite imitating amethyst. In 1986 thousands of grams of this material were sold in Belo Horizonte. Since fluorite is optically isotropic with a density of 3.18, you can detect it with either the polariscope or the bromoform. An examination with the hand loupe will show cleavage, usually in four direction(octahedral). Amethyst has no cleavage, and its hardness is 7 while fluorite’s is 4.
A different kind of falsification is exemplified by a parcel of golden beryl (heliodor), sold in the State of Paraiba in 1986. This ‘heliodor’ was nothing more than colorless beryl (goshenite) treated with a suspension of iron oxide or iron hydroxide to give it a yellowish color. A careful examination with the loupe shows that the coating is not homogenous, and you can see ‘windows’ of colorless beryl. Scratching a small piece with a knife will remove the coating.
Fake mineral specimens
The last and most difficult group to detect is mineral specimens for collectors—the variety is immense. We can divide this group into two categories: falsification strictly speaking, made out of other materials, and those using genuine minerals but glued in various ways.
For instance, pink crystal and watermelon crystal. Closer examination with the loupe is necessary to detect both falsifications The first specimen (pink crystal) consists of a sawn piece of lepidolite (a lithium mica) affixed to a matrix with powdered rubellite (red tourmaline) and cement. The striations are too regular, and with the loupe the granular structure of the coating material is obvious. Mica is also softer than tourmaline. The second example, sold in the city of Teofilo Otoni, Minas Gerais in 1973 for a very high price, simulates a watermelon tourmaline of excellent quality. The center is made from red glass. Green tourmaline, coarsely powdered, was mixed with common construction cement, and a green coating of this together with pieces of natural green tourmaline was applied around the red glass core. Here also, a close examination reveals the granular nature of the outer rim. Usually a huge tourmaline would appear very dark brown down the crystallographic c-axis (optic axis) which this fake does not. In this particular case, the polariscope will not separate glass from tourmaline, since tourmaline behaves isotropically in the direction of the optic axis. Well terminated crystals are of greater value to collectors than unterminated or broken ones. Faceted and polishing a broken end can make a crystal appear terminated. Examine suspicious crystals with the loupe. Polished areas generally look completely different from a natural crystal face. Tourmaline, aquamarine, ‘imperial topaz’, and quartz crystals are the most common minerals falsified in this manner.
The glued specimens of authentic minerals are even more difficult to detect. A specimen of scheelite and gold in matrix from the famous gold mine of Morro Velho, near the city of Belo Horizonte, was sold in 1987. A careful examination with loupe showed that the gold was glued onto the matrix. A piece of ‘canga’ (a conglomerate of naturally crushed rock particles, pebbles, and sand, with an iron oxide/hydroxide cement), with diamond and gold from the Diamantina District, Minas Gerais was seen, and both the diamond and the gold had been glued onto the specimen. Broken quartz crystals, also from the Diamantina region, are often seen glued back together. Since all three specimens do occur naturally, you have to examine the area surrounding the mineral (gold, diamond, or broken place) carefully using your loupe. A crystal or a piece of gold projecting from a crevice or a tiny cavity in the rock should arouse your suspicions.
Reaction of some adhesives to ultraviolet light
Adhesive: Araldite; Color: colorless to white; LW = white/yellowish/pink: very weak; SW = medium
Adhesive: Superbonde; Color: colorless; LW = -; SW = -
Adhesive: Silicone; Color: Colorless to white; LW = white to v.v.weak; SW = -
Adhesive: Durepox; Color: grey; LW = -; SW = -
Adhesive: Pattex Sekundenkleber (Germany); Color: colorless; LW = - ; SW = -
Adhesive: Pattex Extracola De contato; Color: white to yellowish; LW = white weak; SW = white medium
Adhesive: Bindulin Porzelankitt (Germany); Color: colorless to white; LW = violet weak; SW = violet medium
There are many adhesives on the Brazilian market, some of which are imported. Only a few of them fluoresce under ultraviolet light. More difficult to detect are those pieces like gold that are not glued, but rather forced into the matrix with a piece of wood. Examine the gold with the loupe to detect any ‘pushing marks’.
For example: Cut/polished agate with water: Magnification of the brownish/reddish point at the upper part reveals that the age was sawn, drilled with ultrasonic drill, then injected with water, and the hole closed with adhesive. Ten power magnification will show the tiny hole filled with glue, and short wave ultraviolet light shows a bright point of fluorescence.
Conclusions
Most fakes on the Brazilian gem market are easy to detect with basic gemological knowledge and the use of the suggested ‘micro-lab’. Since the number of such falsifications and their varieties is immense, we have discussed only a few typical examples. Remembering these, and imagining all possible variations, the buyer won’t be cheated or misled in most cases. For ‘almost’ flawless emerald, ruby, sapphire and alexandrite with good color and cut, it is better to consult a gemologist with more extensive equipment. Cheap imitations of these stones and the synthetic Verneuil stones are usually poorly cut.
Read on to learn more……
(via The Canadian Gemmologist, Volume XII, Number 1, Spring 1991)
Some Fake Gems On The Brazilian Market And How To Identify Them
Joachim Karfunkel, Reinhard R Wenger, Wolney Lobato writes:
Abstract
After 15 years experience in the Brazilian gem market, the authors suggest a simple ‘micro-lab’ for the detection of imitations and falsifications. Descriptions of some of the most common fakes in cut stones, rough material, and specimens for collectors are given. Simple means for distinguishing them from genuine pieces are discussed.
Introduction
Brazil, a paradise on earth for gems, is also a territory with one of the highest incidences of gem and mineral falsifications. The story of imitations or fakes in gemology is probably as old as the first uses of minerals and similar materials for personal adornment. Webster (1983) writes: “It is, however, faience, a glazed siliceous ware made in Egypt as long ago as pre-dynastic times (before 4777 B.C) which is the more important as a beginning of imitation gemstones.”
We can define imitation as any substance used as a substitute for natural gem that fails to duplicate its composition, structure, and properties. Imitations aim to replace a gem with another cheaper material, which has a similar appearance, but different physical and chemical properties. Those imitations which have the purpose of misleading are called falsifications or fakes. To this group we could also add gems that have been treated to enhance their appearance, and supposed value, but which fade or change with time. Knowledge of these treatments should not be withheld from buyers. Further information on synthetics and gemstone enhancement can be found in Nassau, 1980, 1984.
The market for imitations in Brazil is huge, since most people there can’t afford to buy genuine gemstones. Similarly a metal other than gold is frequently used for settings. Imitations may be sold as genuine, and some regard the Brazilian market as a ‘cheating’ market. We want to emphasize that most of the Brazilian stone dealers are honest. Those few who want to mislead, however, sell their wares to everybody, including friends and even relatives! The problem is increased by lack of gemological education. The basic equipment is the human eye, sometimes aided with tweezers and a loupe. Most of those who possess a polariscope, dichroscope, refractometer, or microscope, usually don’t know how to use them. They sell the stones they bought believing truly that the stones are genuine.
The Micro-Lab
Many tourists, gem dealers and collectors prefer to buy in the interior of Brazil, rather than in the capitals like Belo Horizonte, Rio de Janeiro, Sao Paulo, Salvador, Fortaleza, or Porto Alegre. Obviously, it is very difficult to travel with a complete laboratory. We do not wish to imply that sophisticated equipment like refractometers, microscopes or spectroscopes is not important, but the tourist or collector often can’t afford such things, nor is it always possible to carry them in the field. Instead, we suggest a simple, cheap ‘micro-lab’ consisting of tweezers, loupe, polariscope, heavy liquid, and a hardness scale. Simple equipment can be effective when you understand how to use it.
Commercial polariscopes are usually expensive—why not build your own? Just buy a piece of Polaroid plastic and cut it into pieces about 2” square. Make a small stand (out of any kind of transparent, firm plastic), and glue the polaroid pieces on each side with the vibration directions perpendicular to each other. This polariscope may be used in the same manner as a conventional one. Place a light source (bulb, sunlight or torch) as near as possible to the polariscope. Hold the stone (rough or cut) between the filters with a hand or tweezers; rotate the stone, the polariscope or both, and observe the behavior (isotropic or anisotropic).
Heavy liquids are generally not cheap, but bromoform with a specific gravity of 2.83 at 15ºC can be acquired at relatively low cost. It should be emphasized that bromoform is a toxic substance, to be used only in a well ventilated area. Some practice is required to accurately estimate specific gravity, but the test is quick and even small stones (less than 0.5ct) may be measured accurately. The best method is by comparison: compare the rate of rise or fall of the unknown stone with that of a known one (indicator), possibly one of the specimens in the hardness scale. For example, the specific gravity of quartz is 2.65; beryl 2.7; pink tourmaline 2.05; fluorite 3.18; topaz 3.5; corundum 4.0.
You don’t need to buy a specimen for every number of hardness on the Moh’s scale. Small pieces of corundum (9), colorless topaz (8), quartz (7), feldspar (6), and apatite (5) will provide sufficient range of hardness and density. A piece of window glass, and a pocket knife are also practical. A piece of porcelain is useful to observe streak.
It may also be useful to have an ultraviolet lamp with short and long wave wavelength capabilities to detect adhesive on repaired or constructed specimens. Such a micro-lab is inexpensive and easy to carry.
Types of fakes
As the instances of fakes on the gem market are many, we can describe only a few and how they can be recognized. Imitations and fakes can be divided into three categories: cut stones, rough gem material and specimens for mineral collectors.
Fake faceted stones
Let’s look at the first group, cut and polished stones. You are probably not going to buy a Colombian emerald, an Indian spinel, or a Burma ruby in Brazil. The most common gems on the Brazilian market are topaz (blue and imperial), aquamarine, emerald, tourmaline, chrysoberyl (including cat’s eye and alexandrite), garnet (almandine and spessartine), amethyst, citrine, smoky and rose quartz, chrysoprase, agate, spodumene (variety kunzite), andalusite, sodalite, amazonite, hematite, etc. Less common are yellow beryl (heliodor), pink beryl (morganite), opal, green spodumene (hiddenite), fluorite, cordierite (iolite), kyanite, rhodochrosite, rhodonite, and apatite. More unusual gems like gahnite, petalite, scapolite, phenakite, amblygonite, brazilianite, titanite (sphene), diopside, euclase, etc and diamond will not be considered here.
On the gem market in Europe or the USA, you can find ‘well done’ imitations, sometimes difficult to detect without considerable gemological knowledge and equipment. In Brazil, however, cheap and readily available imitations such as glass, synthetic spinel, and synthetic corundum (both made by the Verneuil method) are common. Rarer are synthetic amethyst (hydrothermal), synthetic emerald (like Gilson and Chatham), synthetic corundum with a color change (Verneuil, alexandrite imitation) etc. Having a closer look at the Brazilian gems, we note that most of them are anisotropic except for garnet, which is isotropic, and agate and chrysoprase, which are cryptocrystalline varieties of quartz with a different behavior under the polariscope. The remaining opal, glass and synthetic spinel are opticall isotropic (with some anomalies). Knowing how to use the loupe and polariscope correctly, you can’t mistake these for one of the above listed gems. Almost all glasses on the Brazilian market have an S.G in the 2.52 region, and will float in bromoform. Most have an R.I around 1.52. An exception, dark violet in color, had S.G 3.18 and R.I 1.618; it sank slowly in bromoform. Don’t forget to use the loupe to look for bubbles and color distribution.
Most of the less common gems are also anisotropic, except opal (compare behavior in the literature) and fluorite. Many faceted violet fluorites were sold as amethyst in Belo Horizonte in 1986. This falsification is easily detected since fluorite is isotropic, and heavier than bromoform (3.18). Amethyst with an S.G of 2.65 floats, and is isotropic. It is much harder too, but hardness tests should not be carried out on a cut stone because they might cause damage.
Unfortunately synthetic emerald, synthetic corundum and synthetic alexandrite are not as easily distinguished from the genuine with the micro-lab, and require better equipment, including a microscope. Don’t buy ‘almost’ flawless stones with an excellent color without consulting a gemologist.
Characteristics of some glasses used as imitations
All the glasses were used to imitate gems of similar color.
Color: Violet; S.G = 2.52; R.I = 1.519; Optics = SR; 10x = Bubbles; Trace elements = Sr, Zr, Ba, La, Ce
Color: Honey yellow; S.G = 2.52; R.I = 1.518; Optics = SR; 10x = Bubbles; Trace elements = Pb, Sr, Ba, Zr
Color: Dark violet; S.G = 3.18; R.I = 1.618; Optics = SR; 10x = - ; Trace elements = Fe
Color: Medium blue; S.G = 2.52; R.I = 1.520; Optics = SR/ADR; 10x = Bubbles; Trace elements = Sr, Zr, Ba
Color: Dark blue; S.G = 2.52; R.I = 1.520; Optics = SR; 10x = - ; Trace elements = Sr, As, Sb
Color: Red yellow; S.G = 2.52; R.I = 1.518; Optics = SR; 10x = Bubbles; Trace elements = As, Se, Zr, Ba, Nd
Color: Green blue; S.G = 2.52; R.I = 1.518; Optics = SR; 10x = - ; Trace elements = Sr, Zr, Sn, Ba
Color: Emerald green; S.G = 2.52; R.I = 1.518; Optics = SR/ADR; 10x = Bubbles; Trace elements = Sr, Zr, Ba
Color: Light blue; S.G = 2.52; R.I = 1.519; Optics = SR; 10x = Bubbles; Trace elements = Sb, Zr, Sr, Ba
Note: The physical and optical properties were determined with an Eickorst refractometer, a Mettler scale, a GIA polariscope, a mineral light with short and long ultraviolet wavelengths, and Zeiss hand loupe 10x. The chemical analyses were kindly provided by Prof C Murtha and Prof R Murta (Nuclebras—Belo Horizonte) using x-ray energy spectrometry (detection limits for the above elements are 100ppm. All specimens are non-fluorescent in ultraviolet light except the red yellow glass, which weakly fluoresced a pale white in short wave UV)
Emeralds from the locality of Santa Terezinha, Goias, and those from Carnaiba/Socoto in Bahia usually have small black inclusions not seen in the synthetics (Gilson/Chatham). Only a few emeralds, some from the localities of Itabira and Nova Era, Minas Gerais, are ‘almost’ without inclusions. The prices are relatively high. So if you are offered such stones for US$200-300 per carat (one carat and larger), you can be sure that you have a synthetic in your hand.
Although corundum exists in Brazil (e.g ruby from Bahia and sapphire from Mato Grosso), the quality is very poor and usually not facetable. What generally appears on the market are Verneuil synthetic ruby and sapphire. Imitation alexandrites are frequently synthetic corundum with color change and not synthetic alexandrite. Synthetic stones of excellent quality, especially in old rings of 18 karat gold, are typically very poorly cut, and sometimes looked crooked. The old rule, ‘excellent gems have a very good cut, whereas low quality gems are poorly cut’ can be applied in this case. In larger stones, characteristic curved growth lines may be seen with the 10x loupe. Many of these stones, especially ruby, shows a very bright fluorescence with both long and short wave ultraviolet light.
Some fakes are so unexpected and simple that many buyers fail to recognize them because they don’t examine things carefully. For example, in the State of Ceara, northeast Brazil, a type of wax made from coconut (cera Carnauba) together with ink from a simple ballpoint pen is applied to white opal. The ink penetrates the opal and darkens it to simulate black opal. Examination with a 10x loupe will show concentration of the dark bluish ink along tiny crevices at the surface.
Falsifications of cat’s eye chrysoberyl may be made by irradiating asteriated quartz cabochons showing unusual strength of one of the rays. The color of the stone will turn brownish yellow, showing one strong ray only, thus imitating cat’s eye. A close look in different directions will reveal the asterism. If you are still in doubt, use the bromoform; chrysoberyl will sink whereas quartz will float.
Falsification of rough gem material
The second group, gem rough, is the easiest to detect, and there are only a few fakes on the market. Glass is commonly used to imitate tourmaline and aquamarine. In the case of tourmaline, green to bluish green glass has been fashioned into prismatic ‘crystals’ and even grooved with a saw to simulate the striations on a natural crystal. Upon magnification, these ‘striations’ appear to too regular. Other fake tourmalines are bicolored (e.g green and blue, green and red, or bright green and olive green) and often have inclusions (impurities). These are made from toy ‘marbles’, small glass spheres. Real tourmaline appears dark to almost black in the direction of the crystallographic axis (its optic axis); these will not. With the loupe it may be possible to detect bubbles in the glass and swirls of color. If there is still doubt, use the polariscope (not in the direction of the optic axis) or the bromoform. Bromoform will not distinguish between common glass and aquamarine, as both float, but tourmaline will sink. The polariscope will leave you without doubt.
Another fake on the market, already mentioned, is violet fluorite imitating amethyst. In 1986 thousands of grams of this material were sold in Belo Horizonte. Since fluorite is optically isotropic with a density of 3.18, you can detect it with either the polariscope or the bromoform. An examination with the hand loupe will show cleavage, usually in four direction(octahedral). Amethyst has no cleavage, and its hardness is 7 while fluorite’s is 4.
A different kind of falsification is exemplified by a parcel of golden beryl (heliodor), sold in the State of Paraiba in 1986. This ‘heliodor’ was nothing more than colorless beryl (goshenite) treated with a suspension of iron oxide or iron hydroxide to give it a yellowish color. A careful examination with the loupe shows that the coating is not homogenous, and you can see ‘windows’ of colorless beryl. Scratching a small piece with a knife will remove the coating.
Fake mineral specimens
The last and most difficult group to detect is mineral specimens for collectors—the variety is immense. We can divide this group into two categories: falsification strictly speaking, made out of other materials, and those using genuine minerals but glued in various ways.
For instance, pink crystal and watermelon crystal. Closer examination with the loupe is necessary to detect both falsifications The first specimen (pink crystal) consists of a sawn piece of lepidolite (a lithium mica) affixed to a matrix with powdered rubellite (red tourmaline) and cement. The striations are too regular, and with the loupe the granular structure of the coating material is obvious. Mica is also softer than tourmaline. The second example, sold in the city of Teofilo Otoni, Minas Gerais in 1973 for a very high price, simulates a watermelon tourmaline of excellent quality. The center is made from red glass. Green tourmaline, coarsely powdered, was mixed with common construction cement, and a green coating of this together with pieces of natural green tourmaline was applied around the red glass core. Here also, a close examination reveals the granular nature of the outer rim. Usually a huge tourmaline would appear very dark brown down the crystallographic c-axis (optic axis) which this fake does not. In this particular case, the polariscope will not separate glass from tourmaline, since tourmaline behaves isotropically in the direction of the optic axis. Well terminated crystals are of greater value to collectors than unterminated or broken ones. Faceted and polishing a broken end can make a crystal appear terminated. Examine suspicious crystals with the loupe. Polished areas generally look completely different from a natural crystal face. Tourmaline, aquamarine, ‘imperial topaz’, and quartz crystals are the most common minerals falsified in this manner.
The glued specimens of authentic minerals are even more difficult to detect. A specimen of scheelite and gold in matrix from the famous gold mine of Morro Velho, near the city of Belo Horizonte, was sold in 1987. A careful examination with loupe showed that the gold was glued onto the matrix. A piece of ‘canga’ (a conglomerate of naturally crushed rock particles, pebbles, and sand, with an iron oxide/hydroxide cement), with diamond and gold from the Diamantina District, Minas Gerais was seen, and both the diamond and the gold had been glued onto the specimen. Broken quartz crystals, also from the Diamantina region, are often seen glued back together. Since all three specimens do occur naturally, you have to examine the area surrounding the mineral (gold, diamond, or broken place) carefully using your loupe. A crystal or a piece of gold projecting from a crevice or a tiny cavity in the rock should arouse your suspicions.
Reaction of some adhesives to ultraviolet light
Adhesive: Araldite; Color: colorless to white; LW = white/yellowish/pink: very weak; SW = medium
Adhesive: Superbonde; Color: colorless; LW = -; SW = -
Adhesive: Silicone; Color: Colorless to white; LW = white to v.v.weak; SW = -
Adhesive: Durepox; Color: grey; LW = -; SW = -
Adhesive: Pattex Sekundenkleber (Germany); Color: colorless; LW = - ; SW = -
Adhesive: Pattex Extracola De contato; Color: white to yellowish; LW = white weak; SW = white medium
Adhesive: Bindulin Porzelankitt (Germany); Color: colorless to white; LW = violet weak; SW = violet medium
There are many adhesives on the Brazilian market, some of which are imported. Only a few of them fluoresce under ultraviolet light. More difficult to detect are those pieces like gold that are not glued, but rather forced into the matrix with a piece of wood. Examine the gold with the loupe to detect any ‘pushing marks’.
For example: Cut/polished agate with water: Magnification of the brownish/reddish point at the upper part reveals that the age was sawn, drilled with ultrasonic drill, then injected with water, and the hole closed with adhesive. Ten power magnification will show the tiny hole filled with glue, and short wave ultraviolet light shows a bright point of fluorescence.
Conclusions
Most fakes on the Brazilian gem market are easy to detect with basic gemological knowledge and the use of the suggested ‘micro-lab’. Since the number of such falsifications and their varieties is immense, we have discussed only a few typical examples. Remembering these, and imagining all possible variations, the buyer won’t be cheated or misled in most cases. For ‘almost’ flawless emerald, ruby, sapphire and alexandrite with good color and cut, it is better to consult a gemologist with more extensive equipment. Cheap imitations of these stones and the synthetic Verneuil stones are usually poorly cut.
The Magic Of Amber
By Rosa Hunger
Chilton Book Company
1979 ISBN 0-8019-6854-2
Chilton Book Company writes:
The Magic of Amber is a fascinating and popular guide to one of the world’s oldest yet least known gemstones. In fact, amber is not a ‘stone’ at all, but a fossilized resin from pine trees that grew some fifty million years ago, and it is part of its mystery and visual appeal that just a few pieces captured for eternity complete insects like flies, spiders and beetles, as well as small flowers, leaves and pieces of bark—presented now in their own miniature ‘showcase’ to be seen and studied all these years later.
But what makes amber so individual is that every piece is unique giving an infinite variety of optical effects in different lights. It is found in a wide range of colors—from the nearly black and deep ruby red, to browns, deep golds and pale yellows, greens and rarer blues, to almost white opaque ambers that resemble ivory. Add to this its warmth, lightness and almost therapeutic quality when touched, and it is small wonder that amber has been so highly prized for thousands of years and has been the object of such fine craftsmanship—particularly in the Orient, Prussia and Germany.
Rosa Hunger has spent all her working life in the amber trade, and there can be few more qualified than her to fill the lengthy gap in English works on amber. Her book is a comprehensive survey of amber from its formation in the depths of time to the latest discoveries in Lithuania and the Dominican Republic. She charts its rises and falls in fashion in the Stone and Bronze ages, Prehistoric, Roman and Medieval times, and describes the achievements of the 16th and 17th centuries—the Golden Age of amber working, the Baroque period to Victorian times and the present day. There are also chapters on rare ambers, how to distinguish amber from its imitations, its care and display, the response of writers to its beauty and the author’s recollections of her family’s trading in amber. Illustrated in both color and black and white, The Magic of Amber will prove of value to collectors, investors and dealers to amber jewelry and objects d’art—or anyone with a feeling for beautiful things, as well as filling a long term gap in the coverage of this glorious gemstone.
Chilton Book Company
1979 ISBN 0-8019-6854-2
Chilton Book Company writes:
The Magic of Amber is a fascinating and popular guide to one of the world’s oldest yet least known gemstones. In fact, amber is not a ‘stone’ at all, but a fossilized resin from pine trees that grew some fifty million years ago, and it is part of its mystery and visual appeal that just a few pieces captured for eternity complete insects like flies, spiders and beetles, as well as small flowers, leaves and pieces of bark—presented now in their own miniature ‘showcase’ to be seen and studied all these years later.
But what makes amber so individual is that every piece is unique giving an infinite variety of optical effects in different lights. It is found in a wide range of colors—from the nearly black and deep ruby red, to browns, deep golds and pale yellows, greens and rarer blues, to almost white opaque ambers that resemble ivory. Add to this its warmth, lightness and almost therapeutic quality when touched, and it is small wonder that amber has been so highly prized for thousands of years and has been the object of such fine craftsmanship—particularly in the Orient, Prussia and Germany.
Rosa Hunger has spent all her working life in the amber trade, and there can be few more qualified than her to fill the lengthy gap in English works on amber. Her book is a comprehensive survey of amber from its formation in the depths of time to the latest discoveries in Lithuania and the Dominican Republic. She charts its rises and falls in fashion in the Stone and Bronze ages, Prehistoric, Roman and Medieval times, and describes the achievements of the 16th and 17th centuries—the Golden Age of amber working, the Baroque period to Victorian times and the present day. There are also chapters on rare ambers, how to distinguish amber from its imitations, its care and display, the response of writers to its beauty and the author’s recollections of her family’s trading in amber. Illustrated in both color and black and white, The Magic of Amber will prove of value to collectors, investors and dealers to amber jewelry and objects d’art—or anyone with a feeling for beautiful things, as well as filling a long term gap in the coverage of this glorious gemstone.
Sunday, March 11, 2007
Dangerous Diamonds
Read on to learn more about scandals behind the sparkle of the world's most desirable gems @
http://www.ex.ac.uk/~RDavies/arian/scandals/diamonds.html
http://www.ex.ac.uk/~RDavies/arian/scandals/diamonds.html
Diamond Smugglers Of Brazil
Here is an interesting profile of diamond smugglers of Brazil. It's educational.
Read on to learn more @ http://foreign-correspondent.blogspot.com/2006/06/diamond-smugglers-ii.html
Read on to learn more @ http://foreign-correspondent.blogspot.com/2006/06/diamond-smugglers-ii.html
Gandhi
Memorable quote (s) from the movie:
Edward R. Murrow (Shane Rimmer): The object of this massive tribute died as he had always lived - a private man without wealth, without property, without official title or office. Mahatma Gandhi was not a commander of great armies nor ruler of vast lands. He could boast no scientific achievements or artistic gift. Yet men, governments and dignitaries from all over the world have joined hands today to pay homage to this little brown man in the loincloth who led his country to freedom. Pope Pius, the Archbishop of Canterbury, President Truman, Chiang Kai-shek, The Foreign Minister of Russia, the President of France... are among the millions here and abroad who have lamented his passing. In the words of General George C. Marshall, the American Secretary of State, "Mahatma Gandhi had become the spokesman for the conscience of mankind, a man who made humility and simple truth more powerful than empires." And Albert Einstein added, "Generations to come will scarce believe that such a one as this ever in flesh and blood walked upon this earth."
Edward R. Murrow (Shane Rimmer): The object of this massive tribute died as he had always lived - a private man without wealth, without property, without official title or office. Mahatma Gandhi was not a commander of great armies nor ruler of vast lands. He could boast no scientific achievements or artistic gift. Yet men, governments and dignitaries from all over the world have joined hands today to pay homage to this little brown man in the loincloth who led his country to freedom. Pope Pius, the Archbishop of Canterbury, President Truman, Chiang Kai-shek, The Foreign Minister of Russia, the President of France... are among the millions here and abroad who have lamented his passing. In the words of General George C. Marshall, the American Secretary of State, "Mahatma Gandhi had become the spokesman for the conscience of mankind, a man who made humility and simple truth more powerful than empires." And Albert Einstein added, "Generations to come will scarce believe that such a one as this ever in flesh and blood walked upon this earth."
The Tourmaline Group
By R V Dietrich
Van Nostrand Reinhold Company
1985 ISBN 0-30-442-21857-5
Van Nostrand Reinhold writes:
Throughout history royalty, mineral collectors, and connoisseurs of colored gemstones have treasured tourmalines for their color, color patterns, durability, and natural beauty. In addition to being exquisite showpieces and gemstones, tourmalines also possess qualities—unique structure, physical properties, and chemical compositions—that have been of great interest to chemist, crystallographers, gemologists, geologists, metallurgists, pedologists and physicists, as well as to mineralogists.
The Tourmaline Group examines the features and characteristics that make tourmalines valuable to scientists and collectors alike. With scores of figures, including eight color plates, the book describes and illustrates the eight species of tourmaline comprising this mineral group and tells how the different species originate in diverse kinds of rocks.
Culling information from more than 2000 publications, the Tourmaline Group surveys such topics as:
- Symmetry and Morphological Crystallography—hemimorphism, crystal size, shape and surface features.
- Physical properties—density, hardness, elasticity, and magnetic, thermal, electrical and radioactive properties.
- Crystal structure—diagrams and easy-to-follow explanations illustrating the arrangement of constituent atoms.
- Color and Optical properties—causes of colors, processes for the enhancement of colors, and the relationship between color and other properties.
- Chemistry and Alternation—the ideal formula for each of the species, an evaluation of chemical analyses of both major and trace elements, and the stability of tourmaline under diverse temperature and pressure conditions.
- Synthesis—experiments indicating how tourmaline may be produced by man.
You will also discover how tourmaline has been used by various civilizations. Dr Dietrich traces the historical roots of tourmaline—from a possible description in Theophrastus ‘On Stones—315 B.C), through its use by the Vikings as a ‘sunstone’ navigation compass, to more recent applications in the manufacture of boric acid, in scientific and industrial instruments and in the decorative arts. And, for readers interested in aesthetics, he devotes a separate chapter exploring tourmaline’s use in jewelry art, and as exhibition pieces.
About the author
R V Dietrich has been an active editor of various mineralogical and geological journals and has been the author or co-author of more than a hundred professional papers and 10 books.
Van Nostrand Reinhold Company
1985 ISBN 0-30-442-21857-5
Van Nostrand Reinhold writes:
Throughout history royalty, mineral collectors, and connoisseurs of colored gemstones have treasured tourmalines for their color, color patterns, durability, and natural beauty. In addition to being exquisite showpieces and gemstones, tourmalines also possess qualities—unique structure, physical properties, and chemical compositions—that have been of great interest to chemist, crystallographers, gemologists, geologists, metallurgists, pedologists and physicists, as well as to mineralogists.
The Tourmaline Group examines the features and characteristics that make tourmalines valuable to scientists and collectors alike. With scores of figures, including eight color plates, the book describes and illustrates the eight species of tourmaline comprising this mineral group and tells how the different species originate in diverse kinds of rocks.
Culling information from more than 2000 publications, the Tourmaline Group surveys such topics as:
- Symmetry and Morphological Crystallography—hemimorphism, crystal size, shape and surface features.
- Physical properties—density, hardness, elasticity, and magnetic, thermal, electrical and radioactive properties.
- Crystal structure—diagrams and easy-to-follow explanations illustrating the arrangement of constituent atoms.
- Color and Optical properties—causes of colors, processes for the enhancement of colors, and the relationship between color and other properties.
- Chemistry and Alternation—the ideal formula for each of the species, an evaluation of chemical analyses of both major and trace elements, and the stability of tourmaline under diverse temperature and pressure conditions.
- Synthesis—experiments indicating how tourmaline may be produced by man.
You will also discover how tourmaline has been used by various civilizations. Dr Dietrich traces the historical roots of tourmaline—from a possible description in Theophrastus ‘On Stones—315 B.C), through its use by the Vikings as a ‘sunstone’ navigation compass, to more recent applications in the manufacture of boric acid, in scientific and industrial instruments and in the decorative arts. And, for readers interested in aesthetics, he devotes a separate chapter exploring tourmaline’s use in jewelry art, and as exhibition pieces.
About the author
R V Dietrich has been an active editor of various mineralogical and geological journals and has been the author or co-author of more than a hundred professional papers and 10 books.
Blame It On Rio
Memorable quote (s) from the movie:
Jennifer Lyons (Michelle Johnson): Will you forget me?
Matthew Hollis (Michael Caine): The minute I die.
Jennifer Lyons (Michelle Johnson): Will you forget me?
Matthew Hollis (Michael Caine): The minute I die.
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