Mohs Scale

n. Mohs Scale of Hardness, scale used to classify minerals according to their relative hardness (Mineralogy)

The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. It was created in 1812 by the German mineralogist Friedrich Mohs and is one of several definitions of hardness in materials science.Mohs based the scale on ten minerals that are all readily available. As the hardest known naturally occurring substance, diamond is at the top of the scale. The hardness of a material is measured against the scale by finding the hardest material that the given material can scratch, and/or the softest material that can scratch the given material. For example, if some material is scratched by apatite but not by fluorite, its hardness on the Mohs scale would fall between 4 and 5.
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Noun
1. a scale of hardness of solids; talc is 0 and diamond is 10; ordering is determined by which substance can scratch another substance
(hypernym) scale, scale of measurement, graduated table, ordered series