Mohs hardness

A ten-point scratch-hardness scale from talc (1) to diamond (10): gypsum 2, calcite 3, fluorite 4, apatite 5, orthoclase 6, quartz 7, topaz 8, corundum 9. A fingernail is about 2.5, a steel knife about 5.5, glass about 5.5.

Sources

Earle, S. (2019). Physical Geology, 2nd ed., Chapter 2: Minerals (CC BY 4.0)
Mindat — Mineralogical glossary (link only)

Cite this article

Stratum Study. "Mohs hardness" (Glossary). Stratum Study pack 2026.09, as of 2026-09-16. https://stratum.black/study/glossary/mohs. Accessed 2026-09-20.

BibTeX · CSL-JSON

@misc{stratum-mohs,
  title        = {Mohs hardness},
  author       = {{Stratum Study}},
  howpublished = {\url{https://stratum.black/study/glossary/mohs}},
  year         = {2026},
  note         = {Glossary article, Stratum Study pack 2026.09, as of 2026-09-16; sources: stratum. Accessed 2026-09-20.}
}

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