---
title: "Color treatment: meaning in gemology"
description: "A color treatment is any process that changes a diamond's color, such as HPHT processing or coating."
url: https://digitalgemology.com/learn/glossary/color-treatment
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

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[Glossary](https://digitalgemology.com/learn/glossary) · Treatments and origin

# Color treatment

Also called treated color

A color treatment is any process that changes a diamond's color, such as HPHT processing or coating.

## In more detail

A stable color treatment such as HPHT is graded and disclosed. Coating is unstable, so GIA doesn't grade a coated diamond.

## On a grading report

GIA adds an asterisk after the color grade and explains the treatment in Comments. It inscribes TREATED COLOR on an HPHT-treated stone.

## Related terms

- [Asterisk after the color grade](https://digitalgemology.com/learn/glossary/asterisk-color-grade): An asterisk (*) after a GIA color grade means that the lab detected a color treatment. Comments explains what it is.
- [HPHT](https://digitalgemology.com/learn/glossary/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.
- [Coating](https://digitalgemology.com/learn/glossary/coating): Coating is a thin film, paint or ink on the surface of a gem that changes its color or look.
- [Treatment](https://digitalgemology.com/learn/glossary/treatment): A treatment is any process, other than cutting and polishing, that changes a gem's color or apparent clarity. Anyone who sells a treated gem must disclose the treatment.

## Learn more

- [Comments, treatments and lab-grown origin on a diamond report](https://digitalgemology.com/learn/grading-reports/diamond-report-comments-treatments-origin)
- [The grades on a diamond report: color, clarity and cut](https://digitalgemology.com/learn/grading-reports/diamond-report-grades)

[All 328 terms](https://digitalgemology.com/learn/glossary)