What's Mineral Hardness?

Have you ever heard that a diamond can scratch glass? Why is a diamond-tipped saw blade better that its counterparts? It is because of a diamond’s hardness. So, what is hardness, and how is it determined?
Hardness is the resistance that a smooth surface offers to scratching. “Scratch hardness” is usually determined by observing the comparative ease or difficulty with which one mineral is scratched by another. Knowing the hardness of the different minerals helps jewelers determine the minerals durability and reaction to different setting techniques.

Friedrich Mohs (1773-1839) was a German scientist who studied minerals. He devised the “scratching” method of testing minerals and their hardness. He found the mineral talc was very soft and assigned the number 1 to talc. He also found that diamond was so hard that no other mineral could scratch it and he therefore assigned the number 10 to diamond.
A series of ten common minerals has been chosen as a scale, by comparison with which the relative hardness of any mineral can be measured. The following group of minerals, arranged in order of increasing hardness, is known as “Mohs’ scale of hardness” .

The following materials are useful in comparison to those listed above.

The following scale of hardness was determined by a sclerometer. If corundum is used as a benchmark of 1000, this scale will demonstrate the wide variance of hardness between minerals.