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Gemstone Encyclopedia
Detailed information for any gemstone you are interested in.
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When you join the IGS community, you get trusted diamond & gemstone information when you need it.
Detailed information for any gemstone you are interested in.
When you join the IGS community, you get trusted diamond & gemstone information when you need it.
Almandine is perhaps the most common garnet species. Forming series wi...
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Rare and difficult to cut, anhydrite is seldom faceted. However, this ...
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Extremely rare as a cut gem, even in very complete collections. Many o...
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Several species of marine mollusks produce stony growths called calcar...
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Professionals will tell you never to trust a trade name used to descri...
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One of the most prized ornamental materials in China, chicken-blood st...
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Marketed as "Gem Silica" this relatively rare, blue to blue-green, opa...
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Any stone that changes color under different types of light is a rare ...
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Color change sapphires are those that change color between light sourc...
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One of the rarest garnet varieties, demantoid can have a green color t...
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Like their marine cousins, many freshwater mollusks can produce pearls...
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Grossular garnets come in almost every color, even colorless, except b...
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It should not be difficult to find numerous small faceted huebnerites ...
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Hydrogrossular differs from the other garnets in that it is never tran...
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Idocrase is one of the lesser known and more beautiful collector gems....
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Malaia or malaya garnets are typically light to dark, slightly pinkish...
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Manganotantalite makes a spectacular red brown gem that is a very rare...
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All three minerals are fibrous or elongated zeolite minerals. Faceted ...
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Niccolite’s delicate peachy red color and metallic luster looks beauti...
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Padparadscha sapphires show a blend of orange and pink colors, one of ...
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Discovered in 1989, paraíba tourmalines are among the world’s most pri...
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Fibrous pectolite has long been a curiosity for gem collectors. Compac...
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Rhodolites are purplish red garnets, a blend between almandine and pyr...
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Usually orange to reddish brown, gem-quality spessartite or spessartin...
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Sphene, also known as titanite, has rich body colors, strong trichrois...
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Although sulfur is very abundant, facetable material is not. Sulfur is...
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Tanzanite has had a rapid rise to prominence among jewelers and gem en...
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Triphylite is one of the world's rarest gems. The IGS had the extraord...
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An emerald-green variety of grossular garnet, tsavorite is one of the ...
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Always a dark, rich green color, uvarovite is one of the rarest member...
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