What is Mohs Hardness Scale
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The Mohs Hardness Scale is used as a convenient way to help identify minerals. A mineral's hardness is a measure of its relative resistance to scratching, measured by scratching the mineral against another substance of known hardness on the Mohs Hardness Scale. This graphic outlines the index minerals and some common objects that are used to determine a mineral's hardness.
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This method is especially useful for identifying minerals in the field because you can test minerals against some very common objects (fingernail, a penny, a nail). The scale is named for its creator, the German geologist and mineralogist Friedrich Mohs. However, the method of comparing hardness has been used as far back as 300 BC, as mentioned by Theophrastus in his treatis On Stones.
Rocks are made up of one or more minerals. According to the scale, Talc is the softest: it can be scratched by all other materials. Gypsum is harder: it can scratch talc but not calcite, which is even harder. The hardness of a mineral is mainly controlled by the strength of the bonding between the atoms and partly by the size of the atoms. It is a measure of the resistance of the mineral to scratching, the Mohs scale is for natural minerals. For manufactured products other measures of hardness are better.
Diamond is always at the top of the scale, being the hardest mineral. There are ten minerals in Mohs scale, talc, gypsum, calcite, fluorite, apatite, feldspar, quartz, topaz, corundum, and for last and hardest, diamond. Because the Mohs scale was made long ago, it is not exactly correct - for example, several minerals are now known to be harder than the diamond. The Mohs scale may not be perfect, but field geologists still find it very useful.
Source Wikipedia
Diamond is always at the top of the scale, being the hardest mineral. There are ten minerals in Mohs scale, talc, gypsum, calcite, fluorite, apatite, feldspar, quartz, topaz, corundum, and for last and hardest, diamond. Because the Mohs scale was made long ago, it is not exactly correct - for example, several minerals are now known to be harder than the diamond. The Mohs scale may not be perfect, but field geologists still find it very useful.
Source Wikipedia
From Visually.