Cut

While the overall beauty of the diamond is apparent through the combination of all four C's, cutting is the most important factor reflecting the brilliance of a diamond. Because there is no defined scale for cutting, it is often difficult to assess a diamonds cutting.

The cut however, when proportioned with precision and skill, release the fire and beauty that truly bring a diamond to life. Diamond "rough" often determines the shape and size of the diamond. Diamond cutters visualize the finished stone will look like even before they make the first cut.

Their job is to maintain weight in the rough diamond while maximizing the brilliance and thus the beauty. A properly cut diamond will directly affect the carat weight of the stone as well. When a diamond is cut to deep, the light entering the diamond will not hit each facet correctly therefore passing much of the light through the diamond before it can reflect back to the eye. This diamond will look smaller than a properly cut diamond of the same carat weight. Likewise, a diamond that is cut too shallow will have poor brilliance as well because the table is larger than a stone of similar weight, it reflects light poorly, causing the diamond to appear quite dull. It is important to take cutting and proportions into account when buying a diamond.