---
title: "Color change: meaning in gemology"
description: "Color change is a visible change of a gem's main hue between daylight and incandescent light."
url: https://digitalgemology.com/learn/glossary/color-change
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

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[Glossary](https://digitalgemology.com/learn/glossary) · Gemstone properties

# Color change

Also called color-change sapphire, color-change effect

Color change is a visible change of a gem's main hue between daylight and incandescent light.

## In more detail

Labs compare daylight of 5500 K to 6500 K with incandescent light of 2700 K to 3600 K. Color-change sapphires often go from blue in daylight to purple in incandescent light. Alexandrite, a chromium-bearing chrysoberyl, also changes color. Pleochroism differs: it changes with the direction of view, not the light.

## On a grading report

Color: [color] in daylight, [color] in incandescent light. Species: color-change [variety].

## Related terms

- [Sapphire](https://digitalgemology.com/learn/glossary/sapphire): Sapphire is corundum of any color other than red. The word alone means a blue stone; other colors take a color word, such as yellow sapphire.
- [Hue](https://digitalgemology.com/learn/glossary/hue): Hue is the basic color of a gem, such as red, blue or green. A second color can modify it, as in purplish red.
- [Pleochroism](https://digitalgemology.com/learn/glossary/pleochroism): Pleochroism is the property of a colored doubly refractive stone to show different colors in different directions. It happens because the stone absorbs its rays differently.
- [Fancy sapphire](https://digitalgemology.com/learn/glossary/fancy-sapphire): A fancy sapphire is a sapphire of any color other than blue, such as yellow, orange, pink, purple or green.

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