Minerals are inorganic substances which occur naturally, which have a definitive crystalline structure and chemical composition. Rocks are made up of one or more minerals. In 1812, German geologist and minerologist Frederich Mohs came up with a way of determining mineral hardness. He devised a scale of ten minerals and ranked them by finding the hardest material that each given material can scratch, and/or the softest material that can scratch each given material. Other substances can be classed by where they fall on this scale. The scale is ordinal, in that each mineral is not exponentially harder than the last. Mohs Scale is:
- Orthoclase (Feldspar)
In the jewellery industry, Mohs Scale is used in determining the identity and authenticity of precious gemstones.