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Mohs scale of hardness

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Mohs, Mohs hardness scale


The so-called Mohs scale assigns the numbers from 1 to 10 to the material hardness: 1 for the softest, 10 for the hardest. It is named after the German geologist and mineralogist Friedrich Mohs (1773-1839). Mohs scratched different minerals against each other and so aligned them according to their hardness. Mohs (MOH) therefore holds as a measuring unit for the material hardness.

Comparison Chart:

Material Mohs hardness
Talc, talcum 1
Plaster 2
Silver 2.5
Gold, aluminium, copper 2.5 - 3
Calcite, marble 3
Plexi-/Acrylic glass, coral 3 - 4
Fluorspar, iron 4
Mineral watch-glass, apatite 5
Steel, porcelain, lapis lazuli, turquoise 5-6
Feldspar, hardened steel 6
Hematite, opal 5.5 - 6.5
Moonstone 6 - 6.5
Agate, Jasper 6.5 - 7
Quartz, rock crystal, amethyst, citrine, onyx and zircon 7
Turmaline 7 - 7.5
Almandine 7.5
Carbide 7 - 8
Aquamarine, beryl, emerald, 7.5 - 8
Topaz, Hardlex watch glass 8
Ruby, sapphire (corundum) 9
Diamond 10