Mohs Hardness Scale
The Mohs scale of mineral hardness ranks 10 reference minerals from 1 (softest) to 10 (hardest). Created by Friedrich Mohs in 1812, it remains the standard for comparing mineral hardness.
Data
| Mohs # | Mineral | Absolute Hardness | Chemical Formula | Common Use |
|---|---|---|---|---|
| 1 | Talc | 1 | Mg₃Si₄O₁₀(OH)₂ | Talcum powder |
| 2 | Gypsum | 3 | CaSO₄·2H₂O | Plaster, drywall |
| 3 | Calcite | 9 | CaCO₃ | Cement, lime |
| 4 | Fluorite | 21 | CaF₂ | Optics, flux |
| 5 | Apatite | 48 | Ca₅(PO₄)₃(OH,F,Cl) | Fertiliser |
| 6 | Orthoclase | 72 | KAlSi₃O₈ | Ceramics |
| 7 | Quartz | 100 | SiO₂ | Glass, electronics |
| 8 | Topaz | 200 | Al₂SiO₄(F,OH)₂ | Gemstone |
| 9 | Corundum | 400 | Al₂O₃ | Abrasives, gems |
| 10 | Diamond | 1500 | C | Cutting, jewellery |
Source: Wikipedia — Mohs scale of mineral hardness. Absolute hardness values are approximate Vickers hardness ratios relative to talc.