Mohs, Mohs hardness scale
The so-called Mohs scale assigns the numbers from 1 to 10 to the material hardness 1 for the softest, 10 for the hardest. It is named after the German geologist and mineralogist Friedrich Mohs (1773-1839). Mohs scratched different minerals against each other and so aligned them according to their hardness. Mohs (MOH) therefore holds as a measuring unit for the material hardness.
| Material | Mohs hardness |
|---|---|
| Talc, talcum | 1 |
| Plaster | 2 |
| Silver | 2.5 |
| Gold, aluminium, copper | 2.5 - 3 |
| Calcite, marble | 3 |
| Plexi-/Acrylic glass, coral | 3 - 4 |
| Fluorspar, iron | 4 |
| Mineral watch-glass, apatite | 5 |
| Steel, porcelain, lapis lazuli, turquoise | 5-6 |
| Feldspar, hardened steel | 6 |
| Hematite, opal | 5.5 - 6.5 |
| Moonstone | 6 - 6.5 |
| Agate, Jasper | 6.5 - 7 |
| Quartz, rock crystal, amethyst, citrine, onyx and zircon | 7 |
| Turmaline | 7 - 7.5 |
| Almandine | 7.5 |
| Carbide | 7 - 8 |
| Aquamarine, beryl, emerald, | 7.5 - 8 |
| Topaz, Hardlex watch glass | 8 |
| Ruby, sapphire (corundum) | 9 |
| Diamond | 10 |