What is the culet on a diamond, and why is a smaller culet preferred?

• A. The culet is the table facet; larger culets increase brilliance.
• B. The culet is the girdle; smaller culets improve durability.
• C. The culet is the small facet at the bottom; a smaller culet reduces light leakage.
• D. The culet is the pavilion facet; size has no effect.

Answer: (C)

The culet is the small facet at the bottom tip of a diamond, sitting on the pavilion. Its historical purpose was to protect the point, and many modern stones have a very tiny culet or none at all. The size matters for light performance: a smaller culet minimizes light leakage out of the bottom, so more light is reflected back through the top and the diamond appears brighter. A larger culet provides a bigger bottom opening for light to escape, which can dull sparkle and, in some lighting, even be seen as a small spot when viewed from above. So, a tiny culet is preferred to maximize optical return and overall brilliance.