Definition of hardness
In mineralogy, hardness is the resistance to scratching or abrasion of one mineral by another. The Mohs hardness scale is a relative scale of 1 (softest) to 10 (hardest) minerals. A mineral with a higher number on the Mohs scale can scratch a mineral with a lower number.
See also: hardness test, hardness scale
When referring to water, hardness refers to the quality of water based on the presence of dissolved calcium or magnesium. See: hard water
See also: hardness test, hardness scale
When referring to water, hardness refers to the quality of water based on the presence of dissolved calcium or magnesium. See: hard water