A scale of hardness used in classifying minerals. It runs from 1 to 10 using a series of reference minerals, and a position on the scale depends on the ability to scratch minerals rated lower.
- ‘On Mohs' scale a finger nail is 2.5; a copper coin 3.5; a knife blade 5.5; and a metal file 6.5-7.’
- ‘Scratch hardness is measured according to the Mohs' scale.’
- ‘So a quick application of Mohs' scale of hardness to the base of the item, using a pocket knife, was employed to satisfy my friend's curiosity.’
Late 19th century: named after Friedrich Mohs (1773–1839), German mineralogist.
We take a look at several popular, though confusing, punctuation marks.