Moh's Scale Of Hardness
Author: Brian Boyle Date Posted:27 April 2015
Mohs Scale Of Hardness
The hardness of any material is defined as its resistance to scratching by other materials. Materials of any particular type are usually fairly consistant in hardness regardless of the locale where they were found.
| Mineral | Hardness |
| Diamond | 10 |
| Corundum | 9 |
| Topaz | 8 |
| Quartz | 7 |
| Feldspar | 6 |
| Apatite | 5 |
| Opal | 5.5 to 6.5 |
| Flourite | 4 |
| Calcite | 3 |
| Gypsum | 2 |
| Talc | 1 |
The relative hardness of any mineral, gemstone or rock in their rough state (finished stones would be severly damaged) can be determined by comparitive scratch test to determine its position in Mohs scale.
The following is a list of materials that can be used for testing stones for their hardness.
| Material | Hardness |
| Silicone Carbide | 9.25 |
| Steel File | 6 to 7 |
| Window Glass | 5.5 |
| Steel Knife Blade | 5.5 |
| Fingernail | 2.5 |