---
title: "CIEDE2000 color difference: meaning in gemology"
description: "CIEDE2000 (ΔE00) is a standard formula for how different two colors look to a human observer. A larger number means a larger visible difference."
url: https://digitalgemology.com/learn/glossary/ciede2000
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

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

# CIEDE2000 color difference

Also called ΔE00, delta E 2000

CIEDE2000 (ΔE00) is a standard formula for how different two colors look to a human observer. A larger number means a larger visible difference.

## In more detail

It works in CIELAB lightness, chroma and hue, with corrections for how the eye sees each region. Our Dichroscope calls a ΔE00 under 1 “none”.

## How we measure it

The Dichroscope uses ΔE00 to class pleochroism through 5 mm in daylight. Ruby reads 17.9 and sapphire 41.6 (strong), emerald 15.3 (distinct) and amethyst 3.3 (weak). We check our formula against the 34 test pairs of Sharma, Wu and Dalal (2005).

## Related terms

- [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.
- [Dichroscope](https://digitalgemology.com/learn/glossary/dichroscope): A dichroscope is a gem-testing instrument that shows a stone's two pleochroic colors side by side. In the calcite type, a calcite rhomb splits the light into two images of a small window.
- [CIE colorimetry](https://digitalgemology.com/learn/glossary/cie-colorimetry): CIE colorimetry turns a light spectrum into a color by weighting it with standard human color-matching functions. Standard illuminants, such as D65 (daylight) and A (incandescent lamp, 2856 K), define the light.

## Learn more

- [Dichroscope](https://digitalgemology.com/about/how-we-measure/dichroscope)
- [Dichroscope](https://digitalgemology.com/tools/dichroscope)

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