IGI diamond is an abbreviation used by diamond dealers to describe diamonds classified by IGI Diamond Identification Laboratory. IGI, the full name of International Gemological Institute, was established in 1975 in Antwerp, Belgium, the capital of diamonds. At present, it is the world's largest independent gemological appraisal laboratory and gemological research and education institution, and its main service scope is jewelry appraisal and professional knowledge education and research. One of the main functions of IGI is to classify diamonds. It has created worldwide diamond 4C standards: color, clarity, cut and carat weight, and solved the problem of highly unified standards in various laboratories. The stability of its diamond quality evaluation results has been widely respected by the industry, so IGI diamonds are one of the conditions for many consumers to buy diamonds.