Mohs' hardness scale - How To Discuss

Mohs hardness scale,

Definition of Mohs hardness scale:

1. Series of ten minerals from the softest to the hardest, so arranged that the mineral with a lower number can be scratched by the mineral with the higher number: 1-talc, 2-gypsum, 3-calcit, 4-fluorite, 5-apatite, 6-orthoclase, 7-quartz, 8-topaz, 9-corundum, 10-diamond. Invented in 1812 by the German geologist Friedrich Mohs (1773-1839).