Friedrich Mohs was born on this day in 1773

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MOHS (mohz)

Mohs scale: A scale for classifying minerals based on relative hardness

Friedrich Mohs: Inventor of a mineral hardness scale

Common clues: ____ scale; Talc-to-diamond scale; Hardness scale; Mineralogist Friedrich

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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.

Frederich Mohs, 1832

On the Mohs scale, a pencil lead has a hardness of 1; a fingernail has hardness 2.5; a copper penny, about 3.5; a knife blade, 5.5; window glass, 5.5; steel file, 6.5.[1] Using these ordinary materials of known hardness can be a simple way to approximate the position of a mineral on the scale.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Mohs Scale".