What is a culet on a diamond?
By Jared James · Last updated 21 May 2026
Definition
The culet is the very bottom of a cut gemstone, at the tip of the pavilion. On modern round brilliant diamonds it is typically polished to a point with no facet, or carries a very tiny one. Older cuts, particularly old European and old mine cuts, often have a larger round culet facet, and looking down through these antique diamonds from above you can sometimes see a small dark circle at the centre, which is light escaping through that open base rather than reflecting back.
Frequently asked questions
- Does the size of the culet affect a diamond's appearance?
- Yes. A very large culet appears as a dark circle when you look through the table of the stone, because light is leaking out of the bottom rather than bouncing back. Modern cutting standards favour no culet or a very small one precisely to avoid this effect.
- Why do antique diamonds have large culets?
- Older cutting techniques used by hand made it difficult to bring the pavilion to a sharp point without risking cracking the stone at its base. The culet facet was a practical solution that protected the tip. It is now considered part of the character of antique cuts.
- Is a chipped culet serious?
- A chip on the culet can be serious depending on its size. The culet is at the most vulnerable point of the stone, and a significant chip there can affect the structural integrity and the way light moves through the pavilion. A jeweller should assess any damage before you continue wearing the piece.
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