Mohs scale(redirected from hardness index)
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A scale for classifying minerals based on relative hardness, determined by the ability of harder minerals to scratch softer ones. The scale includes the following minerals, in order from softest to hardest: 1. talc; 2. gypsum; 3. calcite; 4. fluorite; 5. apatite; 6. orthoclase; 7. quartz; 8. topaz; 9. corundum; 10. diamond.
[After Friedrich Mohs (1773-1839), German mineralogist.]
(Minerals) a scale for expressing the hardness of solids by comparing them with ten standards ranging from talc, with a value of 1, to diamond, with a value of 10
[C19: named after Friedrich Mohs (1773–1839), German mineralogist]
a scale of hardness for minerals, consisting of the following degrees, in increasing hardness: talc 1; gypsum 2; calcite 3; fluorite 4; apatite 5; orthoclase 6; quartz 7; topaz 8; corundum 9; diamond 10.
[1875–80; after French. Mohs (1773–1839), German mineralogist]
A scale used to measure the relative hardness of a mineral by its resistance to scratching. There are ten standard minerals on this scale, ranging from talc, the softest (measuring 1 on the scale), to diamond, the hardest (measuring 10 on the scale).