MOHS Hardness Scale

Description

The Mohs scale of mineral hardness (/moʊz/) is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material. The Mohs scale of mineral hardness is based on the ability of one natural sample of mineral to scratch another mineral visibly. The samples of matter used by Mohs are all different minerals. The minerals are listed from hardest to softest with their hardness scale number as follows: Diamond, 10; Corundum, 9; Topaz, 8; Quartz, 7; Orthoclase, 6; Apatite, 5; Flourite, 4; Calcite, 3; Gypsum, 2; and Talc, 1. The Common Objects for hardness comparisons are listed a column to the left as: Masonry Drill Bit, 8.5; Steel Nail, 6.5; Knife/Glass Plate, 5.5; Copper Penny, 3.5; and Fingernail, 2.5.
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