The culet is the tiny edge of a polished diamond, especially large diamonds, which represents the bottom tip of the diamond. In round diamonds it is the 58th edge.
Polishing is intended to minimize the damage that is likely to occur to the tip of the diamond as a result of rubbing other diamonds and being worn down, or poor closing of one of the lower sides.
The size of the culet must be appropriately proportioned. A small closure is preferable over a large culet, which results in the escape of light rays.
