Although the 1980s did not experience the emergence of several totally new synthetics that characterized the preceding decade, it was during this period that synthetics matured, with many new ...

Scientific advances in the past decade have completely altered our understanding of certain concepts relating to the age and origin of diamonds. As a generalization, most diamonds formed more than 990 ...

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 ...

Advances in technology and increased demand for lower-priced gem materials contributed to the proliferation of new treatments throughout the first decade of the 2000s. The developments that made the ...

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 ...

A relatively new production of red corundum, reportedly from Bangkok, has been offered for sale in recent years. Although the producers claimed that these stones were red diffusion-treated corundum (i ...