Mohs Hardness Scale
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The Mohs scale of mineral hardness is an ordinal scale measuring the hardness of minerals through the abilities of harder materials able to scratch softer materials. Invented by German mineralogist Friedrich Mohs in 1812, it is one of various definitions of hardness in material science.[1]
Mohs hardness | Mineral | Chemical formula | Absolute hardness[2] | Image |
---|---|---|---|---|
1 | Talc | Mg3Si4O10(OH)2 | 1 | ![]() |
2 | Gypsum | CaSO4·2H2O | 3 | ![]() |
3 | Calcite | CaCO3 | 9 | ![]() |
4 | Fluorite | CaF2 | 21 | ![]() |
5 | Apatite | Ca5(PO4)3(OH−,Cl−,F−) | 48 | ![]() |
6 | Orthoclase feldspar | KAlSi3O8 | 72 | ![]() |
7 | Quartz | SiO2 | 100 | ![]() |
8 | Topaz | Al2SiO4(OH−,F−)2 | 200 | ![]() |
9 | Corundum | Al2O3 | 400 | ![]() |
10 | Diamond | C | 1500 | ![]() |
Comparison with Vickers scale
This is a comparison between Mohs's scale and the similar Vicker's scale.
Mineral name |
Hardness (Mohs) | Hardness (Vickers) kg/mm2 |
---|---|---|
Graphite | 1–2 | VHN10=7–11 |
Tin | 1½ | VHN10=7–9 |
Bismuth | 2–2½ | VHN100=16–18 |
Gold | 2½ | VHN10=30–34 |
Silver | 2½ | VHN100=61–65 |
Chalcocite | 2½–3 | VHN100=84–87 |
Copper | 2½–3 | VHN100=77–99 |
Galena | 2½ | VHN100=79–104 |
Sphalerite | 3½–4 | VHN100=208–224 |
Heazlewoodite | 4 | VHN100=230–254 |
Carrollite | 4½–5½ | VHN100=507–586 |
Goethite | 5–5½ | VHN100=667 |
Hematite | 5–6 | VHN100=1,000–1,100 |
Chromite | 5½ | VHN100=1,278–1,456 |
Anatase | 5½–6 | VHN100=616–698 |
Rutile | 6–6½ | VHN100=894–974 |
Pyrite | 6–6½ | VHN100=1,505–1,520 |
Bowieite | 7 | VHN100=858–1,288 |
Euclase | 7½ | VHN100=1,310 |
Chromium | 8½ | VHN100=1,875–2,000 |
References
- ↑ "Mohs hardness" in Encyclopædia Britannica Online
- ↑ Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
- ↑ "Ice is a mineral" in Exploring Ice in the Solar System. messenger-education.org
- ↑ Lua error in Module:Citation/CS1 at line 925: attempt to concatenate local 'str' (a table value).
- ↑ 5.0 5.1 Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).