A burn mark is a hazy area on a facet surface, caused by too much heat during polishing. It is also called a burned facet.
In more detail
It is a blemish. The polish grader looks for burn marks at 10x, with pits, nicks, polish lines and scratches.
On a grading report
A blemish; it can count in the polish grade.
Related terms
- Polish: Polish is the grade for the smoothness of the facet surfaces, from Excellent to Poor. The grader looks at 10x for pits, nicks, polish lines, scratches, burn marks and rough patches.
- Polish lines: Polish lines are fine parallel grooves and ridges left by polishing. They can occur on any facet but don't cross facet junctions, and they look transparent or white.
- Blemish: A blemish is a clarity characteristic confined to the surface of a diamond.