Friedrich Mohs harder. This became the basis of the hardness scale developed by Mohs. The hardest mineral, diamond was given a value of 10 and softer minerals such as talc were given the very low value of 1 (unity). Other minerals were given intermediate values, depending on their ability to scratch another mineral in the scale. Thus gypsum was given the value 2 because it will scratch talc crystals, and calcite the value 3 because it will scratch gypsum. Minerals are also now classified by chemical characteristics, but the physical properties are still useful in field examination. In 1812, Mohs became a
Schiehallion including dog's mercury, lily of the valley and wood anemone. The majority of Schiehallion consists of Quartzite, a rock formed from an original sand by heat and pressure. Quartzite is a white or pinkish rock, in which the dominant mineral is Quartz. Quartz is hard, being number seven on the Mohs scale of mineral hardness. It is able to scratch glass since it is harder than glass. People often mistakenly think that Schiehallion is an extinct volcano because its shape is reminiscent of an active volcano. If fact it formed by sedimentary processes and the shape is the result of