An asterisk (*) after a GIA color grade means that the lab detected a color treatment. Comments explains what it is.
In more detail
For example, HPHT processing can remove or change a diamond's color. GIA then marks the grade, describes the treatment in Comments and inscribes TREATED COLOR on the girdle. An asterisk without an explanation in Comments is a sign that something on the report is wrong.
On a grading report
Directly after the color letter, for example "H*".
Related terms
- Color treatment: A color treatment is any process that changes a diamond's color, such as HPHT processing or coating.
- HPHT: HPHT stands for high pressure, high temperature. The same conditions can grow a diamond in a laboratory or treat a natural one to change its color.
- Comments: Comments is the report section for identifying characteristics or features that have no other line on the report. It is also where the lab describes a treatment that it detected.
- Color grade: The color grade is a letter from D to Z for the yellow or brown tint of a near-colorless diamond. D is colorless and Z is light yellow or brown.