The diamond appraisal certificate issued by American Jewellery Institute proves that internationally renowned diamond appraisal institutions have laser codes consistent with the certificate at the waist of diamonds, which can also be found in official website. GIA was founded in Los Angeles 193 1. It founded and put forward the international scoring system. Headquartered in Los Angeles. The college is trusted by the world in diamond classification and gemstone identification, and is famous for its knowledge and expert position in gemstones. In fact, GIA diamond classification report and GIA diamond processing are considered to be the first gem certificates in the world. Diamonds of all sizes are sent from all corners of the world to the college for analysis and classification.

The breakthrough research of American Gemological Institute and its own education, experiment and equipment development process are almost the chronicle of the growth of jewelry industry. Since 1953, Richard T. Liddicoat founded and popularized this international diamond grading system, it has become the most respected and authoritative diamond grading appraisal institution in the United States. GIA ensures the credibility of jewelry and diamonds by discovering, imparting and applying gemological knowledge. Guy Margel, the president with a degree in geology, was founded in 1974 and opened the first EGL appraisal center in Antwerp, Belgium. And to help consumers buy diamonds and precious stones as their own responsibility. For more than 30 years, EGL's customers are mainly professional wholesalers, retailers and cutting factories. EGL also provides appraisal and teaching services. In addition, it also provides diamond polishing. The certificate issued by EGL is enough to provide all the information of diamonds, including physical properties such as weight, color, clarity and size, for the reference of the industry and consumers. In the United States and Belgium, EGL certification has a certain professional status and popularity.