The Mohs hardness scale is a relative scale usually used for minerals and does not involve any measurement of deformation, as do other quantitative methods. It simply involves the assignment of a ...

Geologists do it according to the Mohs Scale of Hardness. There. That’s your “hardness” joke for the post. Now down to business, with the hardest (and softest) scale there is. In 1812, people had just ...