The value of a diamond is determined by two factors - size and quality. Size is defined by a diamond's carat weight. The combination of the other three Cs make up the diamond's quality. Each "C" can be measured and assigned a grade by a gemological certification lab, and every Hearts On Fire diamond is submitted to the lab at the American Gem Society (AGS). The AGS lab is renowned for its stringent grading standards, and is the only lab in the world that assigns a definitive grade for a diamond's Cut. They adhere to the internationally accepted grading scale developed by the (GIA) for assigning Color and Clarity grades.