What is a pit on a diamond or gemstone?
By Jared James · Last updated 21 May 2026
Definition
A pit is a small indentation on the surface of a diamond or gemstone, usually too tiny to see with the naked eye but visible under magnification. It often forms at the end of an internal fracture that reaches the surface, or where a tiny crystal was lost during cutting and polishing. Pits count as surface blemishes when a gemologist assesses clarity, and a concentration of them across a stone's table can affect how well it reflects light.
Frequently asked questions
- Does a pit affect the look of a diamond?
- A single small pit rarely affects appearance in everyday wear; you would need magnification to spot it. Multiple pits clustered across the table facet can scatter light and reduce brilliance, which is why they are noted on grading reports.
- Can a pit be polished away?
- A jeweller can sometimes re-polish a surface blemish like a pit, though this removes a tiny amount of material and slightly reduces the stone's weight. Whether it is worth doing depends on the pit's size and where it sits.
- How does a pit appear on a diamond certificate?
- On a GIA or similar grading report, pits are plotted as surface blemishes on the clarity diagram, usually marked with a small dot. They are factored into the overall clarity grade along with any other inclusions.
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