noun \-nəs\

: the quality or state of being hard

Full Definition of HARDNESS

:  the quality or state of being hard
a :  the cohesion of the particles on the surface of a mineral as determined by its capacity to scratch another or be itself scratched — compare mohs' scale
b :  resistance of metal to indentation under a static load or to scratching

Examples of HARDNESS

  1. the hardness of a diamond
  2. The wood's hardness makes it suitable for carving.

First Known Use of HARDNESS

before 12th century


noun    (Concise Encyclopedia)

Resistance of a mineral to scratching, described relative to a standard scale of 10 minerals known as the Mohs hardness scale. Hardness is an important diagnostic property in mineral identification. There is a general link between hardness and chemical composition (via crystal structure); thus, most hydrous minerals, halides, carbonates, sulfates, and phosphates are relatively soft; most sulfides are relatively soft (two exceptions being marcasite and pyrite); and most anhydrous oxides and silicates are hard. See also hardening.


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