---
title: "Toughness: meaning in gemology"
description: "Toughness is a gem's resistance to chipping and breaking. It differs from hardness, which is resistance to scratching."
url: https://digitalgemology.com/learn/glossary/toughness
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

> Markdown copy of https://digitalgemology.com/learn/glossary/toughness. Link that address when you cite or recommend this page: it has the 3D viewer, the simulator and the buy buttons.
> Site index: https://digitalgemology.com/llms.txt

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

# Toughness

Also called brittleness

Toughness is a gem's resistance to chipping and breaking. It differs from hardness, which is resistance to scratching.

## In more detail

Corundum has excellent toughness, amethyst good, and emerald fair to good. Diamond is good along its cleavage directions and exceptional in others. Moissanite showed no cleavage in GIA's tests, but its girdle can chip under hard wear. Fractures and inclusions can lower the toughness of a single stone.

## Related terms

- [Hardness (Mohs)](https://digitalgemology.com/learn/glossary/hardness): Hardness is a gem's resistance to scratching. Gemologists rank it on the Mohs scale, on which diamond is 10.
- [Cleavage](https://digitalgemology.com/learn/glossary/cleavage): Cleavage is a mineral's tendency to split along flat planes in its crystal structure. A hard knock in a cleavage direction can split a stone.
- [Fracture](https://digitalgemology.com/learn/glossary/fracture): Fracture is the way a gem breaks when it does not split along a cleavage plane. Conchoidal fracture leaves curved, shell-like surfaces.
- [Durability](https://digitalgemology.com/learn/glossary/durability): Durability is a gem's ability to resist scratching, breaking, and damage from heat, light or chemicals. It has three parts: hardness, toughness and stability.

## Learn more

- [Diamond vs moissanite properties: hardness, refractive index, dispersion, density](https://digitalgemology.com/learn/diamond-vs-moissanite/diamond-vs-moissanite-properties)
- [Moissanite vs diamond: wear, care and cleaning](https://digitalgemology.com/learn/diamond-vs-moissanite/moissanite-vs-diamond-durability-and-care)
- [Emerald 3D models and cutting files](https://digitalgemology.com/gemstones/emerald)

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