Classification of 10 levels of increasing hardness to compare mineral substances according to Mohs on the basis of Vickers hardness HV:
1. Talk --
2. Gips 36
3. Kalkspat 140
4. Flußspat 190
5. Apatit 540
6. Feldspat 600 – 750
7. Quarz 900 – 1280
8. Topas 1430
9. Korund 1800
10. Diamant 10000