Gemological Institute of America (GIA) created the diamond grading system; known as the 4 Cs. Only GIA and the American Gem Society (AGS) uphold the highest standards during the diamond grading process.
Brilliance, fire, and sparkle––three exciting characteristics all specially cut diamonds possess. In fact, the cut of a diamond is considered the most important of the four C's: clarity, color, carat weight, and cut. "Brilliance" refers to the intensity of light reflected by a diamond. The intensity of "fire" within a diamond indicates how well it disperses light to produce a vivid rainbow of colors. Sparkle, or "scintillation," describes a diamond's ability to shimmer as it moves in light.