This chart combines a comprehensive listing of the commercially available treatments for the most commonly used gem materials with an indication of the current status of their detectability.

High-quality synthetic diamonds created by the Gemesis Corp. are examined and their gemological properties are explicated.

This article chronicles the discovery of primary diamond deposits throughout Canada, whose increasing supply of rough stones will have a growing impact on the world diamond industry.

Known for their great beauty and rarity, pink diamonds have long been sought after by jewelers, collectors, and consumers.

A relatively new production of red corundum, reportedly from Bangkok, has been offered for sale in recent years.

Although the Pinctada margaritifera oyster usually is associated with the black pearls cultured in French Polynesia, it also can produce attractive large yellow cultured pearls, among other colors.

This article presents the first complete gemological characterization of the historic 128.48 ct Brazilian diamond known as the Star of the South.

On this occasion—the celebration of Richard T. Liddicoat’s 50 years guiding Gems & Gemology—it is fitting to review his enormous impact on the field of gemology.

Vivid blue, green, and purple-to-violet cuprian elbaites, renowned in the gem trade as “Paraíba” tourmalines, continue to be recovered in small amounts from northeastern Brazil.

Jewelry designer Paula Crevoshay showcases the work of some of North America’s leading lapidaries.

For most of the 20th century, the principal source of fine spessartine was the area around the Little Three mine near the town of Ramona in southern California.

This second major article in a three-dimensional modeling study analyzes fire – the visible extent of light dispersed into spectral colors.

Several gems were recently examined that showed stars with an unnatural appearance or an unusual number of rays.

A comparison study was made between the yellow and white nacre of the gold-lipped Pinctada maxima oyster shell and 65 yellow cultured pearls.

Chinese freshwater cultured pearls (FWCPs) are assuming a growing role at major gem and jewelry fairs, and in the market at large.