Ruby is the July birthstone – and it’s one of the most coveted of gems. The name is derived from the Latin word ruber, meaning “red” – the color of love and passion. Few things catch the eye like the ...

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 ...

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 ...

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 ...

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 ...

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.

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 ...

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 ...

GIA studied more than 400 important gemstones from the Gübelin Collection and is committed to sharing this repository of gemological information. This work is a valuable resource for all students, ...

The green turquoise cabochon, from an American mine, might become part of a designer’s unique jewelry piece. The even blue color of the cabochon on the right would be called “Persian blue” in the ...

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 ...

Diamonds have a long history as beautiful objects of desire. In the first century AD, the Roman naturalist Pliny stated: “Diamond is the most valuable, not only of precious stones, but of all things ...