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Gemology
by Russell Shor, GIA senior industry analyst
In the nearly sixty years since the first synthetic diamonds were created, 2012 may be remembered as the year when they made a major impact in the market for gem-quality diamonds.
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by Robert Weldon, GG. GIA Manager of Photography & Visual Communications
GIA attended the Arusha International Gem and Mineral Fair to learn how it can serve the local community with gemological education and resources.
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There is no gemstone in the world quite like a diamond. Formed by nature, the average diamond is 3.3 billion years old. Rare and valuable, a diamond is a testament of endurance and strength, with unsurpassed brilliance and fire—a natural symbol of everlasting love.
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Garnet actually is a group or family of mineral species with related chemical compositions in cubic form that can differ widely in their physical properties and appearance
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Tanzanite is a spectacular blue, violetish-blue or bluish-purple variety of the mineral Zoisite, which is colored by vanadium. Initially discovered as small surface crystals in 1962
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Tourmaline is a complex borosilicate mineral family. When certain members of that family add copper, manganese and a trace amount of gold to their composition, a cuprian or Paraiba tourmaline results.
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Gemologists place diamonds in categories called type Ia, Ib, IIa, and IIb. Each category has its own characteristics and color variations. The classification system is based on the presence (or absence) and type of impurity element.
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by Donna Beaton GIA, New York
In September 2011, GIA was informed by Dudley Blauwet (Dudley Blauwet Gems, Louisville, Colorado) about a new find of citrine, which was represented to him as natural-color material from the Kitwe area of Zambia.
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by Amy Cooper and Phil York GIA, Carlsbad
Any gem with elongated needle inclusions or a fibrous structure can produce chatoyancy when cut as a cabochon with the proper orientation.
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by Nathan Renfro GIA, Carlsbad
Recently examined in the Carlsbad laboratory was an 11.52 ct purplish red cushion mixed cut.
Gemological testing confirmed the material was corundum
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by Kyaw Soe Moe GIA, New York
At the 2012 Tucson gem shows, Mark Kaufman (Kaufman Enterprises, San Diego, California) revealed a relatively new find of yellow opal. According to his supplier, the opal reportedly came from West Africa,
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by Gagan Choudhary Gem Testing Laboratory, Jaipur, India
Mehul Durlabhji, co-convener of the Gem Testing Laboratory of Jaipur, India, recently brought two cabochons to this contributor for identification. The specimens, one green and one orangy yellow,
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by Sally Eaton-Magaña GIA, Carlsbad
em-quality synthetic diamond grown by chemical vapor deposition (CVD) is rarely encountered among the stones submitted for a GIA diamond report. Rarer still are type IIb CVD specimens—most are type IIa.
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by Akira Hyatt GIA, New York
In July 2012, the New York laboratory received a most unusual pearl for examination. The 26.99 x 17.90 x 7.25 mm specimen bore an uncanny likeness to a mushroom, consisting of a bell-shaped cap atop a narrower stem.
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Among the many elements represented on the Chart of Elements is a group known as the "Noble Metals." These metals distinguish themselves by being remarkably resistant to chemical reactions, corrosion and oxidation
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