HOW GEMSTONES AND DIAMONDS ARE GRADED
If you are going to spend a substantial amount of money on a diamond or a colored gemstone, it is imperative to learn how gems are graded. National Gemstone utilizes the world's foremost independent grading laboratories. These two labs are the Gemological Institute of America (GIA) for diamonds and the American Gemological Laboratories (AGL) for colored gemstones.
The leading international auction houses utilize the AGL and GIA laboratory reports for important diamonds and colored gemstones. These independent labs do not buy or sell gems, but act as impartial intermediaries between buyers and sellers.
These grading systems are comprehensive and require some study. However, once you grasp an understanding of the basic principles, you will wonder how anyone could buy or sell a gemstone without these vocabularies.