Examines the mining and the internal, spectroscopic, and chemical features of peridot from this deposit, which possesses a rich olive green color and is available in large sizes.

The Carlsbad lab received a rhodochrosite cabochon featuring rhomboid-shaped fluid inclusions, causing a four-rayed star.

Contributes to the mining history of Austria’s Habachtal region, which is believed to be one of the earliest emerald deposits.

Unique diamond- and emerald-lensed spectacles from the Mughal Empire were tested in GIA’s New York laboratory.

The first installment of this column discusses the formation of colored stones from the crust-mantle transition and below.

Researchers examine six specimens of banded turquoise, obtained through long-term cooperation of local miners in Zhushan County.

Distinguished research fellow Dr. James Shigley receives the Robert M. Shipley Award for his contribution to the science of gemology.

Although spinel is rarely treated, there have been some heated spinels available in the trade.

A colorless topaz from Nigeria hosts the only known example of willemite as an inclusion in topaz.

The Tokyo lab examined a stunning double cat’s-eye emerald whose chatoyancy was created both by its cut and its inclusions.

A group of large, high-quality CVD material demonstrates the continued challenge of identifying laboratory-grown gems.

Creative faceting highlights an octahedral-shaped cloud inclusion in a 2.01 ct diamond octahedron.