The cut of a diamond refers to everything man has done in the process of converting it from a piece of rough, natural diamond material into a finished gemstone capable of the beautiful brightness and sparkle which makes diamonds the most popular of all precious gems. The details of cut include shape, make, angles, proportions, optical precision, weight ratio, facet symmetry and final polish. These specifics all combine to determine how the diamond will appear as it travels through the world’s many lighting conditions.
Most Important. Least Discussed.
Although geometry is the most important component for diamond beauty, it’s typically discussed far less than color and clarity in most places. One reason is that color and clarity grading are easily learned by new sales professionals. But understanding the many details of optics requires a stronger commitment, as well as foundations in geometry and physics. It’s worth noting that most diamonds are made to average quality and in-depth discussions about geometry would reveal that lack of quality in average stores. The fact that many grading labs include little or no information about the make only underscores the resistance to education felt in commercial markets.
Diamonds in the top few percent of the world’s cut actually improve in the other Cs: They appear larger for their carat weight, face up more colorless and clarity characteristics can be less visible. Most importantly, they explode with dazzling whiteness and rainbow colors, even away from jewelry store lighting where most diamonds go dark.
Helps Size Appearance:
A diamond designed for the highest level of visual performance appears larger than diamonds of average cut quality because they are bright all the way from edge-to-edge, not just bright in the center.
A diamond with the critical angles and precision needed for highest performance has shorter ray-paths reducing face-up color; in some cases by multiple grades.
A diamond planned for highest performance boasts superior brightness and scintillation, even when removed from jewelry store lighting, which helps to “mask” inclusions.
Different laboratories have radically different standards. Please see our page on Grading Laboratories for more information.
Brilliant and mixed shapes like round brilliant, princess and cushion, have a different “flavor” than step cuts such as emerald and asscher.