---
title: "Chatoyancy: meaning in gemology"
description: "Chatoyancy is a single band of light that glides across a gem, like the slit eye of a cat. Light reflects from many aligned, needle-like inclusions."
url: https://digitalgemology.com/learn/glossary/chatoyancy
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

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

# Chatoyancy

Also called cat's-eye effect, cat's eye

Chatoyancy is a single band of light that glides across a gem, like the slit eye of a cat. Light reflects from many aligned, needle-like inclusions.

## In more detail

The stone must be cut as a cabochon to show it. Asterism is two or more chatoyant bands that cross.

## On a grading report

Labs name the phenomenon, for example cat's-eye chrysoberyl.

## Related terms

- [Asterism](https://digitalgemology.com/learn/glossary/asterism): Asterism is a star of light that glides across the dome of a gem. Light reflects from fine needles, often rutile, that lie in two or three directions.
- [Needle](https://digitalgemology.com/learn/glossary/needle): A needle is a thin, elongated crystal inclusion that looks like a tiny rod at 10x.
- [Silk](https://digitalgemology.com/learn/glossary/silk): Silk is a mass of fine, crossing needle inclusions, usually rutile, in ruby and sapphire.

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