This describes the polish, symmetry and proportions of the diamond, which ultimately determine its brilliance, fire and sparkle. A skilled cutter uses precise workmanship and artistry to fashion a diamond so it delivers maximum visual effects, including brightness (external and internal reflected light), fire (the scattering of light into each color of the rainbow), and scintillation (the sparkle and pattern of light produced by reflections within the diamond).
Diamond Cut Quality
The cut grade depends on the quality of a diamond’s finish, proportions and symmetry. When a rough diamond reaches the hands of a diamond cutter, they create the shape and cut of the diamond. A well-cut diamond will appear brilliant and sparkly, while a poorly cut diamond may appear dark and dull.
Types of Diamond Cuts
If the cut of a diamond is too deep, some light escapes through the side of the stone. If the cut is too shallow, light escapes through the bottom of the stone before it can be reflected, thus reducing its brilliance. The pattern of cut surfaces — or facets — represents the quality of the cut and has a direct effect on the overall brilliance. With well-proportioned cuts, light reflects from one facet to another, then back through the top of the diamond.
Each grading lab uses their own grading scale and terminology to determine a diamond’s cut, based on the level of precision (or the quality of the cut).