What is the Point of a Culet?
Culet is the name of the bottom-most part of the diamond. In a round cut diamond, the culet could be a finely sharpened point or a flat surface. When it is a flat surface, it acts as a window parallel to the diamond’s table, which can appear as an inclusion and is thought to be undesirable. In some cultures, the “open” flat surface is said to allow evil spirits into the diamond. In either case, a pointed culet has its detractors as well. A pointed culet breaks more easily while the jewel is being set. For these reasons, the role of the culet has gone back and forth over time. However it is the modern vogue to have a “closed” pointed culet, not visible to the naked eye.
A culet grade of “none,” “very small,” or “small,” will still allow for an overall GIA cut grade of “excellent.” The highest GIA cut grade associated with a “medium” culet is a “very good” cut grade. A culet graded “slightly large” or “large” may earn a “good” GIA cut grade at best. A “very large” culet can do no better than a “fair” cut grade, and an “extremely large” culet automatically earns the “poor” GIA cut grade.