International Gemmological Institute (IGI) New York

AGTA Gemological Testing Center

The American Gem Trade Association Gemological Testing Center (AGTA GTC) is the natural colored gemstone industry's premier independent laboratory.   The AGTA GTC serves the industry and the public with a complete range of colored gemstone and ...

American Gemological Laboratories (AGL)

The American Gemological Laboratories is an independent organization which grades colored stones and diamonds.

Universal Gemological Laboratory

GIA Gem Trade Laboratory

Gemological Institute of America

GIA Gem Trade Laboratory Reports are regarded throughout the gem and jewelry industry worldwide as the hallmark of integrity, reliability, and consistency in gemological services and research. The Laboratory has literally set the industry standard for dia ...