The Top 5 Hardest Substances on Earth

  Substance Chemical Formula Absolute Hardness
1 Diamond (C) 1500
2 Corundum (Al2O3) 400
3 Topaz (Al2SiO4(OH-,F-)2) 200
4 Quartz (SiO2) 100
5 Orthoclase Feldspar (KAlSi3O8) 72
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Sources:  Top 5 of research 2012.

List Notes: Data is naturally occurring minerals according to absolute hardness. Absolute hardness is measured by a sclerometer.

Please note: Top 5 of has not included lonsdaleite or Wurtzite boron nitride on this list because they have to be synthesized in a laboratory by compressing and heating in order to attain a higher hardness than diamond. However if they were to be included on this list Wurtzite boron nitride would have a Mohs of 11.0 and an absolute hardness of 1888 (ranking 2nd). Ionsdaleite would have a Mohs of 12 and an absolute hardness of 2528 (ranking 1st).
Hardest  Substances on Earth

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