---
title: "Hardness (Mohs): meaning in gemology"
description: "Hardness is a gem's resistance to scratching. Gemologists rank it on the Mohs scale, on which diamond is 10."
url: https://digitalgemology.com/learn/glossary/hardness
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

> Markdown copy of https://digitalgemology.com/learn/glossary/hardness. 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

# Hardness (Mohs)

Also called Mohs hardness, hardness, scratch resistance

Hardness is a gem's resistance to scratching. Gemologists rank it on the Mohs scale, on which diamond is 10.

## In more detail

Diamond is 10, moissanite 9.25, ruby and sapphire 9, and cubic zirconia 8 to 8.5. Emerald is 7.5 to 8 and amethyst 7. Mohs is a ranking, not a ruler: diamond is far harder than corundum. Hardness is not toughness, so a hard stone can still chip.

## How we measure it

Our gemstone pages give each stone's Mohs hardness.

## Related terms

- [Mohs scale](https://digitalgemology.com/learn/glossary/mohs-scale): The Mohs scale ranks minerals from 1 to 10 by which can scratch which. Diamond is 10 and corundum is 9.
- [Toughness](https://digitalgemology.com/learn/glossary/toughness): Toughness is a gem's resistance to chipping and breaking. It differs from hardness, which is resistance to scratching.
- [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.
- [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.
- [Scratch](https://digitalgemology.com/learn/glossary/scratch): A scratch is a thin, dull white line across the surface with no clear depth at 10x.

## 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)
- [Diamond 3D models and cutting files](https://digitalgemology.com/gemstones/diamond)
- [Ruby 3D models and cutting files](https://digitalgemology.com/gemstones/ruby)
- [Emerald 3D models and cutting files](https://digitalgemology.com/gemstones/emerald)
- [Amethyst 3D models and cutting files](https://digitalgemology.com/gemstones/amethyst)
- [Cubic Zirconia 3D models and cutting files](https://digitalgemology.com/gemstones/cubic-zirconia)

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