A highly saturated purplish pink to red pezzottaite from a new deposit in Madagascar is encountered in Tucson and tested by GIA researchers.

A chemical and spectroscopic comparison of two purple gem spinel samples, one of them the first reported example of a spinel with a saturated purple color caused predominantly by chromium and cobalt.

Malaya garnets from Bekily, Madagascar, are predominantly pink to pinkish orange, with some stones orange to red. Discovered only in the late 1990s, the majority are intermediate members of the pyrope ...

View the holiday schedule for all GIA locations worldwide.

To commemorate the 50th anniversary of The Wizard of Oz, Harry Winston created real ruby slippers set with 4,600 rubies. - Courtesy Harry Winston Red is the color of our most intense emotions—love and ...

With the withdrawal of Soviet troops from Afghanistan, villagers in the Panjshir Valley are turning their attention to the emerald riches of the nearby Hindu Kush Mountains.

With the increasing use of radiation to color enhance gemstones, the issue of radioactivity has become a source of concern for gemologists worldwide.

A large number of natural-color yellow diamonds are analyzed using grading and appearance aspects among other characteristics to clarify the differences between them and the light yellow diamonds ...

Peer Reviewed Gems & Gemology, Spring 2009, Volume 45, No. 1 Hackmanite/Sodalite from Myanmar and Afghanistan David Kondo and Donna Beaton ...

GIA ensures accurate gemological measurements across its global laboratories through rigorous metrology practices, including systematic instrument calibration, validation from traceable standards, and ...

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 ...

An examination of the skull-melting technique used to produce cubic zirconia, first introduced in 1976, as well as the market status of this diamond simulant and information about its production and ...