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 ...

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 ...

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 ...

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 ...

Visit us at the 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 onsite ...

The definition of padparadscha has always been debated. GIA has studied the history of the term and its modern use and indicates on a Colored Stone Identification & Origin Report when a sapphire, in ...

To convert your current GIA report to a different report type, submit the gemstone along with its original GIA report and note that you would like Report Conversion service on your Service Order ...

In 2009, GIA bestowed its highest honor, the Richard T. Liddicoat Award for Distinguished Achievement, on longtime chief research gemologist John I. Koivula. The award was based on his contributions ...

Harness the power of knowledge with the industry-leading instruments that GIA uses in its grading laboratories. Representing more than 85 years of research and the combined expertise of GIA’s ...

合成宝石材料是在实验室中制成的一种材料，但却具有与其相对应的天然矿物相同的化学、光学和物理特性，虽然在某些情况下，如合成土耳其石和合成蛋白石，可能会有其他化合物的存在。

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.

三月的两种生日石海蓝宝石和血石在外观上有着很大的差异，但在庇佑人们幸福安康这方面，二者都享有盛誉。海蓝宝石生日石让人想起大海的颜色。从深绿-蓝到淡弱绿蓝色的色彩，刻面海蓝 ...