ˈmōz-, -ōs(ə̇z)- noun
Usage: usually capitalized M
Etymology: after Friedrich Mohs died 1839 German mineralogist
1. : a scale of hardness for minerals ranging from 1 for the softest to 10 for the hardest in which 1 represents the hardness of talc; 2, gypsum; 3, calcite; 4, fluorite; 5, apatite; 6, orthoclase; 7, quartz; 8, topaz; 9, corundum; 10, diamond
2. : a revised and expanded version of the original Mohs' scale in which 1 represents the hardness of talc; 2, gypsum; 3, calcite; 4, fluorite; 5, apatite; 6, orthoclase; 7, vitreous pure silica; 8, quartz; 9, topaz; 10, garnet; 11, fused zirconia; 12, fused alumina; 13, silicon carbide; 14, boron carbide; and 15, diamond