The Mohs hardness scale is a scratch resistance test that can be applied to various minerals. It was created in 1812 by German geologist Friedrich Mohs and is one of several tests used to document mineral hardness. Minerals are rated on a scale of one through ten with each number correlating to a different mineral type. The mineral that is to be tested is scratched by a mineral from the scale system, and the final result is determined by documenting whether the mineral surface is scratched by a mineral of known hardness. The Mohs hardness scale is considered an arbitrary gauge and is not considered accurate for industrial materials, such as steel or ceramic.
See chart below for the Mohs hardness mineral scale:
| Mineral | Mohs Hardness | Observations |
| Talc | 1 | Easily scratched by fingernail |
| Gypsum | 2 | Can be scratched by fingernail |
| Calcite | 3 | Easily scratched with sharp metal edge |
| Apatite | 5 | Can be scratched with sharp metal edge, not easily |
| Orthoclase | 6 | Cannot be scratch with sharp metal edge, can scratch glass with difficulty |
| Quartz | 7 | Easily scratches glass |
| Topaz | 8 | Very easily scratched glass |
| Corundum | 9 | Cuts glass |
| Diamond | 10 | Used as a glass cutter |