Gemological Institute of America – The foremost gemological education organization in the world, based in Carlsbad, CA with other locations in NYC and many countries. Graduate Gemologist (GG) is a title given to graduates. They also created the GTL to offer reliable, conservative gemstone grading to the consumer and trade members. They are also known as the inventor of the current Four C’s diamond grading system.

According to their website:

“GIA’s mission is to ensure the public trust in gems and jewelry by upholding the highest standards of integrity, academics, science, and professionalism through education, research, laboratory services, and instrument development.”