Answer:
During the early 1800s, a German mineralogist named Friedrich Mohs devised a scale that tested mineral hardness, which means the resistance of a mineral to being scratched. This scale, which ran from 1 to 10, was named after Mohs, and is known as the Mohs Hardness Test. (Hardness should not be confused with brittleness. Diamond, the hardest known natural substance, can produce a scratch on virtually all other substances, but can easily be shattered by the blow of a hammer.) Keep in mind that the Mohs scale does not indicate exact hardness, which depends upon the purity of the mineral sample and its degree of crystallinity. The Mohs Scale is shown below, using commonly known minerals to represent each degree of hardness:
Talc
Gypsum
Calcite
Fluorite
Apatite
Feldspar
Quartz
Topaz
Corundum
Diamond
