As a consumer, you will regularly encounter in the marketplace gems that have been treated to change their appearance. A topic that often comes up is whether a particular gemstone is or isn’t treated.

Search a city or postal code to find retailers who carry GIA-graded diamonds or have GIA-trained staff. Results will include addresses, store hours and directions. Store hours reflected on Retailer ...

Students examine the technical expertise needed to grade, buy, and sell diamonds with the insight of a seasoned professional. Coursework explores the GIA diamond grading procedures to assess the 4Cs – ...

GIA is proud to provide the most comprehensive research in the industry with a world-renowned field gemology team and a dedication to acquiring colored stones directly from the source. Our ...

Emeralds are again being mined in the historic district of the Ural Mountains. Physical, chemical, spectroscopic, and microscopic characteristics of stones from the recent production are presented and ...

Synthetic emeralds grown hydrothermally in an alkali-free, chlorine-bearing solution have been manufactured in Guilin, China, since 1987. Diagnostic microscopic features include growth and color ...

Attractive yellow to light greenish yellow gem scapolites have been mined from a skarn deposit near the town of Ihosy, in southern Madagascar, since the late 1990s. Chemical analysis indicates that ...

GIA通信教育では、現在と同じ生活をお過ごしになりながら、宝石とジュエリーの資格を得て専門家としての知識を広げることができます。 通信教育の仕組み メディア豊富な教材が ...

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, ...

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, ...

Sapphire comes in a variety of colors. This rare 1,126.00-ct. corundum crystal’s pinkish orange color is called padparadscha, named after the lotus flower. - © GIA ...