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hardness
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hardness

The resistance of a material to indentation by various means, such as scratching, abrasion, wear, and drilling. Methods of heat treatment can increase the hardness of metals. A scale of hardness was devised by German–Austrian mineralogist Friedrich Mohs in the 1800s, based upon the hardness of certain minerals from soft talc (Mohs hardness 1) to diamond (10), the hardest of all materials.

Hardness is often measured by the Brinell hardness test. The hardness of water refers to the presence of dissolved minerals that prevent soap lathering and form scum, particularly compounds of calcium and magnesium. Treatment with a water softener may remove or neutralize them.



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