Twenty-six peridot samples from the Esquel pallasite meteorite and 27 samples from 10 terrestrial sources were studied by laser ablation–inductively coupled plasma–mass spectrometry (LAICP- MS). Among ...

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Since Robert Crowningshield's discovery in the late 1950s that diamonds that have been artificially colored by irradiation and subsequent annealing could be identified by their characteristic ...

This article examines the sophisticated techniques and equipment currently used to fashion a polished gem from a rough diamond. The basic manufacturing techniques— sawing, bruting, blocking, and ...

Following up on Nassau's 1981 article on the technical aspects of heat treating ruby and sapphire, the author reports his personal observations of the actual heat treatment process in Bangkok. He ...

Visit us at the 70 th Bangkok Gems & Jewelry Fair to learn what’s new at GIA and take advantage of quick, convenient gem identification and origin identification services for colored stones at our ...

Visit us at the Bangkok Gems & Jewelry Fair to learn what’s new at GIA and take advantage of quick, convenient gem identification and origin identification services for colored stones at our onsite ...

Data for global annual rough diamond production (both carat weight and value) from 1870 to 2005 were compiled and analyzed. Production statistics over this period are given for 27 diamond-producing ...

Heating is an accepted treatment for sapphire. But for fine-quality sapphire, confirmation from an independent laboratory like GIA that there is no evidence of heat adds to a sapphire’s rarity and ...

Large crystals of chromium-containing synthetic forsterite are being commercially manufactured for use as a laser material. Considerable color variation is possible, and some of this material ...

Cultured pearls come in different sizes, shapes, and colors. Perhaps the best-loved gems of all time, pearls—both natural and modern cultured pearls—occur in a wide variety of colors. The most ...

This 7.19-carat alexandrite was cut to feature its beautiful color change. When the light source changes from daylight to incandescent light, the gem’s color changes from bluish green to reddish ...