Hardness | Mineralogy4Kids
The hardest mineral known, diamond, was assigned the number 10. How does the hardness scale work? The Mohs Hardness Scale ranks the order of hardness of minerals and some common objects. For example, your fingernail can scratch the minerals talc and gypsum, with a hardness of 2 or lower. A copper penny can scratch calcite, gypsum, and talc.