Mohs Scale of Hardness

Mohs Scale was developed in 1812 by German mineralogist Friedrich Mohs (1773-1839)

Mohs Scale of hardness is a RELATIVE scale, not proportional. I mean by this that a mineral with the hardness of 8 will NOT be twice as hard as a 4. (For example, diamond is 4X harder than sapphire!).

It is really a scale of relative "scratchability".

#1 is softest..................#10 is hardest

1. Talc
2. Gypsum
3. alcite
4. Fluorite
5. Apatite
6. Feldspar
7. Quartz
8. Topaz
9. Corundum
10. Diamond

From http://www.gemologyonline.com/mohs.html