Diamond cut grade is one of the four C's of diamonds, which include clarity, cut, color and carat weight. The cut doesn't refer to the shape, but it refers to how the facets are cut. A diamond with a good cut will have a high level of shine, as well as proportionate facets and parts of the diamond. If a diamond cut is too shallow or too deep, the reflective light will escape through the bottom or the side of the diamond. This takes away from the brilliance of the stone.
The Diamond Cut Scale Ranges