7.9-cm tall crystal. Both are from Sappat, Kohistan, Pakistan. - Jeffrey Scovil Gem miners find peridot as irregular nodules (rounded rocks with peridot crystals inside) in some lava flows in the ...

When General Electric created the first gem-quality synthetic diamonds in 1971, the first place the company sent them after cutting was to GIA for examination and research. In the 44 years since then, ...

Designed for clients who seek in-depth insights into every aspect of a jewelry item. Comprehensive analysis of the diamonds in an item, including number of stones, shape, estimated carat weight, color ...

From late June to mid-September 2003, seven important gem diamonds went on temporary public display at the Smithsonian Institution in Washington, DC, in an exhibit titled “The Splendor of Diamonds.” ...

The Robert Mouawad Campus at GIA World Headquarters in Carlsbad offers world-class gem studies with advanced classrooms, a renowned lab, and an iconic museum.

Fine-color, large, and eye-clean (lacking visible inclusions) rubies like this 11.01carat (ct) stone from Myanmar (formerly known as Burma) are extremely rare and valuable. – Photo: Robert Weldon/GIA.

Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive.

With proper care, kunzite jewelry will provide a lifetime of beautiful adornment. - Courtesy Loretta Castoro Signature Collection Hardness and Toughness Gem and mineral hardness is measured on the ...

A synthetic gem material is one that is made in a laboratory, but which shares virtually all chemical, optical, and physical characteristics of its natural mineral counterpart, though in some cases, ...

With the emergence of opal production in Wollo, Ethiopia, the supply of hydrophane opal has increased significantly. This deposit offers beautiful material at a fraction of the price of ...

The red and green dyes in this bracelet’s amber pieces can fade over time. Hardness and toughness Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or ...

Figure 1. Pleochroism in a 15 ct tanzanite, as seen with the unaided eye through the crown and the pavilion sides and ends. Photo by Wimon Manorotkul. In describing colored gemstones, the major ...