top of page

4 diamond appraisal institutes (GIA/IGI/HRD/AGS)

Diamond certificate is a comprehensive inspection report for diamond, and the report will list the four grading (also called 4C – carat, color, clarity and cutting) of that diamond. Such reports are mainly issued by international appraisal institutes, and are something that would come with when you purchase diamonds. Among the jewelry industry, the most globally well-known international appraisal institutes are GIA, IGI, HRD and AGS. The 4 institutes contributed greatly to diamond appraisal and brought significant improvement to the diamond appraisal system.


1. Gemological Institute of America

GIA is the first institute that globalizes the issuing of diamond certificates. It was founded by Mr. Robert Shipley in 1931, and has a history of around 86 years. GIA is a non-profit organization sponsored by jewelry industry, and is authority when it comes to appraising and rating. GIA also spares no effort in gemstones research and education. It often excavates and studies different kinds of gemstones and the methods in managing them. The institute is also enthusiastic about training jewelry professionals and promotes the unique knowledge of gemology.




2. International Gemological Institute

IGI was founded in 1975, with its headquarter in Antwerp, Belgium, the world diamond center. It is the largest independent gemstone appraisal laboratory and gemstone researching education institute in the world. IGI is also the first laboratory in the world that issue jewelry appraisal certificate. It laid down the milestone of gemstone appraisal as it is the first that use laser to leave permanent marking on diamond and study diamond cutting. IGI drawn up the first comprehensive diamond cut grade chart, which serves as the loose standard for modern grading of diamond cutting.




3. HRD Antwerp

Under the advocacy of Belgium government and representatives from jewelry industry, HRD was founded in 1973 and became an officially recognized organization representing jewelry merchants in Belgium. In the global jewelry market, HRD Antwerp represents the Antwerp jewelry industry and acts as the subsidiary of AWDC. It underwent reorganization in 2007 and was spilt into two independent corporations. AWDC specializes in promoting the trading and manufacturing of raw gemstone and finished products, while HRD focuses on diamond appraisal. HRD is now a leading diamond appraisal institute in Europe.




4. American Gem Society

AGS was founded by Robert M. Shipley in 1934. In early 1990s, AGS strived to develop the grading system of diamond. Unlike other appraisal systems, AGS rated the cut, color and clarity of a diamond through a grading from 0, which is the best, to 10, which is the worst. Other than that, AGS diamond grading system formulizes the cut grade from the 4C. This brought a new perspective to analyze the cut grade of diamonds.




GIA, IGI, HRD and AGS are all well-famed and authoritative appraisal institutes in the jewelry industry. All of their grading certificates are the results of strict and precise evaluation. When you purchase diamonds, it is advised that you choose one authorized by the above mentioned institutes for guaranteed quality.


bottom of page