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The Epic Interactive Encyclopedia 1998
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Epic Interactive Encyclopedia, The - 1998 Edition (1998)(Epic Marketing).iso
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Hardness
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1992-09-02
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Physical property of materials that governs
their use. Methods of heat treatment can
increase the hardness of metals. A scale of
hardness was devised by 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.
See also Brinell hardness test. The hardness
of water refers to the presence of dissolved
minerals in it that prevent soap lathering,
particularly compounds of calcium and
magnesium. Treatment with a water softener
may remove or neutralize them.