Relative and Absolute Hardness Scale
Scratch hardness Mohs |
Mineral used for comparison |
Simple hardness tester |
Cutting resistance (Rosiwal) |
1 |
Talc |
Can be scratched with fingernail |
0.03 |
2 |
Gypsum |
Can be scratched with fingernail |
1.25 |
3 |
Calcite |
Can be scratched with copper coin |
4.5 |
4 |
Fluorite |
Easily scratched with knife |
5.0 |
5 |
Apatite |
Can be scratched with knife |
6.5 |
6 |
Orthoclase |
Can be scratched with steel file |
37 |
7 |
Quartz |
|
120 |
8 |
Topaz |
|
175 |
9 |
Corundum |
|
1000 |
10 |
Diamond |
|
140,000 |