The Mohs Hardness Scale was developed by Friedrich Mohs in 1812.  The scale was created by testing which specific materials could scratch other materials, therefore, determining the hardness of each material.  He used 10 minerals in his test and by doing this he found that Diamond was the most scratch resistant material and Talc was the least.  There other minerals that he compared were Gypsum, Calcite, Fluorite, Apatite, Orthoclase, Quartz, Topaz, and Corundum.

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