Hardness is defined as resistance to scratching; the hardness of a gemstone shows how well this gem resists abrasion (see Gemstones hardness chart). It is one of the main considerations when choosing and mounting a gemstone in jewelry.
The Mohs hardness scale was created by a German mineralogist Friedrich Mohs (1773-1839). Mohs studied mathematics, physics and chemistry. He classified minerals by their physical characteristics, in spite of their chemical composition and this scale is one of the ways that gemologists use to determine the hardness of gemstones.
There are ten materials on the Mohs scale of mineral hardness and they are listed from soft to hard. The hardness is graded between 1 (talc) and 10 (diamond). Talc is the softest mineral and has a hardness of 1, Diamond has a hardness of 10 on this scale and it is the hardest natural material known to man. Hardness can be tested through scratching (A mineral can only be scratched by a harder substance).
