Mohs Hardness Scale

Mohs Hardness Scale is a 10-point hardness scale of minerals describing resistance to scratching. Created in 1812 by the Viennese mineralogist Friedrich Mohs. He created the concept of relative hardness to determine minerals. Relative hardness is defined as the resistance a mineral offers when being scratched by a sharp object. According to the scale, minerals are arranged from the softest to the hardest. Each mineral in the Mohs scale can scratch a mineral of a lower scale or be scratched by a mineral of a higher scale. The softest reference mineral is talc, while the hardest is diamond. All known minerals are assigned to the Mohs hardness scale. In practice, there are also half degrees, e.g. morganite achieves a relative hardness of 7.5-8.

Reference minerals (from softest to hardest):

1. talc

2. gypsum

3. calcite

4. fluorite

5. apatite

6. orthoclase

7. quartz

8. topaz, morganite, emerald

9. corundum (sapphire, ruby)

9.5. moissanite

10. diamond