Of all the 4Cs, Cut has the greatest effect on a diamond’s beauty. In determining the quality of the cut, the grader evaluates the cutter’s skill in the fashioning of the diamond; technology assesses the diamond’s light performance.
Diamonds have a unique ability to manipulate light efficiently. This unique ability can be released and maximized only by cutting and polishing the diamond to an extremely high level of accuracy.
Cut is much more than just the shape of the diamond (round, oval, square, etc.).
Diamonds must be cut and polished in order to release their true beauty. It is only when the smooth facets are polished on the diamond that it truly comes to life. A little knowledge about how diamonds are shaped in nature and what a cutter must do to make them sparkle will help you understand Cut. It is the cut of a diamond that will make a person fall in love with it. A diamond can be flawless and colorless, but it will not be beautiful if it does not dance with light. Good cutting also can disguise lower color and can override lower clarity due to dazzling light return. There is value in that, too.
The cutting process is time-consuming, requires specialized tools, and demands expert training and craftsman skill levels. The cutter must study the rough carefully, set the angles properly, and polish carefully, or the final product will appear lifeless. For instance, if the pavilion of a diamond is too deep, the diamond will appear dark and dull. If the pavilion is too shallow, reflections of the girdle will be seen through the table. If the table is too large, the resulting surface reflection will be distracting and the fire (rainbow colors) will be reduced. If the girdle is too thick, the gemstone will be difficult to set in a mounting and to keep secure. If either the girdle or the crown is too thin, the gemstone will chip easily. It is important to remember these causes and effects; any one of them will affect value and possibly durability. Without advanced training, it is difficult to tangibly identify any of the particular faults, but knowing they exist will assist in understanding the beauty of diamonds.
When creating the finished diamond, there are reasons why a diamond cutter makes compromises. As the cutter strives for the maximum weight retention from the rough and tries to create the largest diamond possible, he may choose to sacrifice the best balance of light return. This is truly a case of “Beauty is in the eye of the beholder.” Good cutting is the key to a beautiful diamond and the most obvious factor a person can appreciate.
Symmetry and polish are collectively described as finish, but each is an important separate element in a beautifully cut diamond. Symmetry considerations include the size, alignment, and matching of the individual facets. Polish refers to the surface condition of the diamond. For instance, if polished too quickly, polish lines might appear as minute scratches on a facet’s surface. It is even possible for the cutter to burn the diamond. (A burned facet has a milky appearance — as if the diamond needs cleaning). These characteristics are evaluated and rated on their overall impact on the beauty of the diamond. Most polish characteristics can be removed easily with repolishing and with very little weight loss.
The term Ideal Cut may be familiar. This sometimes is used to describe a diamond that has been cut with exceptional thought to proportions and finish. There have been and will continue to be changes and opinions on one true ideal.