hardness
  • The relative resistance a material has to scratching, denting, bending, penetration, and/or wear, as determined by a standard test. For example, the relative resistance a material has to scratching, as indicated by the Mohs hardness scale.
  • The relative readiness with which radiation, especially X-rays, penetrates matter. The shorter the wavelength, the greater the hardness, and the more penetrating the rays.

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