#hardness  the property of being rigid and resistant to pressure; not easily scratched; measured on Mohs scale
  exclusion:  #softness
  supertype:  #consistency__consistence__body  the property of holding together and retaining its shape; "when the dough has enough consistency it is ready to bake"
  subtype:  #firmness  the property of being unyielding to the touch
  subtype:  #incompressibility  the property of being incompressible
  subtype:  #Brinell_number  measure of the hardness of a material

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