A comprehensive look at Texas topaz, detailing its gemological and compositional characteristics and providing a basis for using trace element concentrations to identify its origin. Bohemian Garnets ...

This article examines the origins of gemstone treatment. Using such primary sources as Pliny's History and the relatively unknown Stockholm Papyrus, the author has uncovered many ancient references to ...

This large Australian light opal cabochon weighs 117.85 carats. Small play-of-color flashes of orange and green predominate in a pinfire pattern, with spots of a more muted blue over a grayish ...

Large quantities of rubies—both rough and faceted—from a commercially important new source in Myanmar (Burma) have been available on the Bangkok market since 1992. The ruby crystals from the Mong Hsu ...

Lapis lazuli has been mined from the Coquimbo Region of Chile since 1905. Some of this material approaches the quality of fine lapis lazuli from Afghanistan. The Chilean material is composed of blue ...

Laser sawing of diamonds is beginning to revolutionize the diamond-cutting industry. Not only does the laser saw offer savings in time and money, but it also enables the cutting of material virtually ...

John Rakovan, Gloria A. Staebler, and Donald A. Dallaire, Eds., 124 pp., publ. by Lithographie LLC, Denver, 2013. US$35.00. As with other titles in this series, this work is a collection of articles ...

This sapphire from Kashmir has an intense velvety blue color. – Photo: Robert Weldon/GIA. Sapphire is one of the Big three of jewelry colored gemstones—the other two are ruby and emerald. A durable ...

Blue diffusion-treated sapphires are becoming more prevalent than ever before. The diffusion technique, which involves the addition of color-causing chemicals during heat treatment, results in a thin ...

Full 4Cs assessment with a plotted clarity diagram, and an assessment of growth type and post-growth treatment. The laboratory-grown diamond’s girdle is laser inscribed with the term "Laboratory-Grown ...

The People's Republic of China has recently placed a high priority on identifying and developing its gemstone resources. Initial exploration by teams of geologists throughout China has identified many ...

Adjacent amethyst and citrine colors in the same crystal of quartz have been reported from South America, although there appears to be uncertainty as to the exact locality of origin. Such material has ...