Mohs Hardness Scale
Mohs hardness is measured on a scale from 1 to 10 with softer minerals designated by low numbers and harder minerals designated by high numbers. The scale was developed about 200 years ago by Friedrich Mohs.
Mohs scale number (mineral example)
Hardness of other common objects
Copper penny: 3
To figure out the hardness of a mineral, try to scratch it with an object of known hardness. For instance, if a fingernail cannot scratch a mystery mineral, we know it has a hardness of more than 2.5. If the mystery mineral can't scratch glass, we know it has a hardness of less than 5.5.
Last modified May 1, 2003 by Lisa Gardiner.
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