Natural Crystals & Gemstones Hardness.

We can measured minerals hardness by trying to scratch it with other minerals or objects of known hardness.

The scale of hardness known as Mohs Scale was established in 1822 by the mineralogist Friedrich Mohs. Minerals with higher Mohs numbers will scratch those lower on the scale. 

Mohs Scale

  No.  Mineral, Scratched by

1. Talc, Fingernail (easy to mark)
   
2. Gypsum, Fingernail (harder to mark)
   
3. Calcite, Copper coin
   
4. Fluorite, Penknife blade (easy to mark)
   
5. Apatite, Penknife blade (harder to mark)
   
6. Orthoclase, Steel file (easy to mark)
   
7. Quartz, Steel file (harder to mark)
   
8. Topaz, Steel file (difficult to mark)
   
9. Corundum, Steel file (very difficult to mark)
   
10. Diamond, Diamond (only Diamond can scratch Diamond)
    

~FJ, Natural Crystals & Gemstones.