GeoMiner Free earth-science tools

Built by a geologist

Hardness identification and geology

A mineral's resistance to scratching, quantified by the Mohs hardness scale 1–10 . Hardness is determined by the strength and density of chemical bonds within the crystal structure and is one of the most reliable and commonly used diagnostic properties in mineral identification. It is tested by attempting to scratch the mineral with reference materials of known hardness. Field: mineralogy. Example: Quartz Mohs 7 will easily scratch feldspar Mohs 6 and glass 5.5 , but cannot scratch topaz Mohs 8 —this systematic scratch-testing is the basis of the hardness test.. Related terms: Mohs scale, Tenacity, Streak, Cleavage.

  • Browse all geology and mining glossary terms — Compare this entry with the complete GeoMiner glossary collection.
  • Previous: Groundmass — The fine-grained or glassy matrix of a porphyritic igneous rock that surrounds the larger, more prominent phenocrysts.
  • Next: Hornblende — A common dark-colored amphibole mineral with the generalized formula Ca,Na ₂–₃ Mg,Fe,Al ₅ Al,Si ₈O₂₂ OH ₂, found in a wide variety of igneous and…
  • Streak

Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T15:19:42.027557+00:00
Review status
Published; not independently peer-reviewed
  • USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
  • Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.

Read GeoMiner's editorial methodology or report a content issue.

Common questions

What does Hardness mean in geology?
A mineral's resistance to scratching, quantified by the Mohs hardness scale 1–10 . Hardness is determined by the strength and density of chemical bonds within the crystal structure and is one of the most reliable and commonly used diagnostic properties in mineral identification. It is tested by attempting to scratch the mineral with reference materials of known hardness.
What is an example of Hardness?
Quartz Mohs 7 will easily scratch feldspar Mohs 6 and glass 5.5 , but cannot scratch topaz Mohs 8 —this systematic scratch-testing is the basis of the hardness test.
Which earth-science field uses the term Hardness?
Hardness is used in mineralogy.
Which terms are related to Hardness?
Related terms in this reference are Mohs scale, Tenacity, Streak, Cleavage.

JavaScript is loading the interactive GeoMiner experience. The identification tools provide educational candidates, not laboratory confirmation.