When it comes to determining the value of a diamond, there is a strict process in which a diamond will undergo a series of examinations by one or several of the different gemological institutes or laboratories. The diamond will be given a grade along with a detailed report, which will be issued by a gem expert. This process is sometimes called diamond certification and it is what many reputable diamond jewellery dealers and retailers use to help determine the value of the diamond.
For the report itself, there are several notes and details about the diamond that will be included such as the colour of the diamond, the clarity of the diamond, the weight of the diamond, the dimension of the diamond, and the purity of the diamond itself. There are other things that could be included in the report such as location where the diamond was mined and other characteristics like proportion and shape of the stone as well. When it comes to certified diamonds, the report gives both the buyer and seller the peace of mind that the diamond they are buying is of the quality that they are paying for.
Most diamonds that are certified are over a certain carat weight, typically 0.25 and greater, due to the cost of obtaining such a written evaluation report of the stone. For diamonds that are smaller in weight with the need to get a certification report completed, this may be obtained at the owners expense. The different institutions around the world that provide such reports for diamond certifications would be the International Gemological Institute (IGI), American Gem Society (AGS), Gemological Institute of America (GIA), European Gemological Laboratory Antwerp (EGL), and the Hoge Raad voor Diamant (HRD). An example of such reports could be found on any of their websites and throughout the internet.
International Gemological Institute, found in 1975, is a large independent institute that is well-known in the diamond certification industry for their experience for diamond certification. Each year they issue more reports for diamond certification than any other laboratory or institute worldwide. The American Gem Society has been dedicated to the diamond certification industry since their establishment in 1934. They are highly viewed as one of the most trustworthy diamond certification institutes in the world. Established in 1931, the Gemological Institute of America has graded some of the most famous diamonds of the world today and could quite possibly be the most recognizable name in the industry. They are also the creator of the 4 Cs of diamonds. The European Gemological Laboratory was established in 1973 and is known for their complete diamond classifying reports. The Hoge Raad voor Diamant was also established in 1973 and is best known for issuing reports on loose polished diamonds.