http://www.gia.edu

GIA is the World's Most Trusted Name in Diamond Grading and Gemstone Identification
The GIA Diamond Grading Report and the GIA Diamond Dossier are considered the world's premier gemmological credentials. Diamonds of all shapes and sizes are sent to the Institute from every corner of the globe for analysis and grading.

A Tradition of Science and Education
Established in 1931, GIA is the world's largest and most respected non-profit institute of gemmological research and learning. GIA applies (through the GIA Gem Laboratory and GIA Gem Instruments) gemmological knowledge to ensure the public trust in gems and jewellery. With nearly 900 employees, the Institute's scientists, diamond graders, and educators are regarded, collectively, as the world's foremost authority in gemmology.

Some of the more celebrated stones graded by GIA include: the Hope Diamond (45.52 carats), the Steinmetz Pink (59.60 carats), the Taylor-Burton Diamond (69.42 carats), the Allnatt (101.29 carats), the De Beers Millennium Star (203.04 carats), the Centenary Diamond (273.85 carats), and the Incomparable Diamond (407.48 carats).

A History of Discovery and Innovation
The Institute's history of education, research, laboratory services, and instrument development reads much like a chronicle of the jewellery industry's own growth and sophistication. GIA is the creator of the famous 4Cs of diamond value (colour, clarity, cut, and carat weight). It is also the corporate birthplace of the International Diamond Grading System™. Today, GIA's D-Z color-grading scale and GIA's Flawless - I3 clarity-grading scale are recognized by virtually every professional jeweller and savvy diamond buyer in the world. The Institute is also known for having developed and patented the first modern jeweller's loupe.

"Every diamond should come with a grading certificate from an accredited gemmological laboratory; the jewellers we talked to agree that the Gemmological Institute of America, an independent non-profit organisation, is the most trustworthy."

Source: GIA