Diamond Cut: Many people confuse diamond cut with the shape of a diamond. Unlike shape, diamond cut is used to evaluate the precision and quality of the overall cutting itself. Diamond Cut usually takes into consideration 3 criteria: Proportions, Symmetry and Polish. Sometimes light performance or other tests can be used to also calculate the precision of the diamond cut.
Symmetry measures how well the facets match the other facets. Polish is a measure of the surface finish. Proportions determine how light is reflected from one facet to another and then how it is dispersed through the top of the stone as shown in the image below.
Diamond Cut is perhaps the most important of the four Cs, so it is important to understand how this quality affects the properties and values of a diamond. We often recommend our customers to consider at least a GIA Excellent or Very Good cut grade within the Proportions, Symmetry and Polish criteria.