It has been established for more than 70 years. Is the founder of diamond 4C, and is the standard to measure the value and quality of diamonds, namely, carat, color, clarity and cut. It is a non-profit diamond appraisal institution, and its diamond certificate is very credible.

Two. IGI, International Gemological Institute.

The production process of each gem certification certificate of IGI is very complicated, and its purpose is to ensure that all aspects of jewelry quality match. IGI, on the other hand, pays more attention to the cut judgment of diamonds than the color grading identification.

AGS, American Gemological Society.

Its founder is also the founder of American Gemological Institute. AGS certificates also classify color, cut and clarity. Through strict classification standards, like our primary consumers, we can understand the classification of diamonds with simple numbers.

Fourth, HRD, Belgian Diamond High Council.

It divides waist circumference, crown height and bottom depth in detail. HRD certificate is more popular than GIA in Europe, but in China, people prefer GIA certificate.

The above four are the major diamond appraisal institutions in the world. Generally, only diamonds with a score of more than 30 points will be issued with certificates, so watch carefully when buying.