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
Fuchsite chemist and mineralogist Johann Nepomuk von Fuchs. Fuchsite crystallizes in the monoclinic crystal system. Common colour of the mineral is pale green to emerald green depending on the amount of Cr substitution. The micaceous crystals are flexible and slightly sectile with a hardness of 2-2.5 on the Mohs scale. Fuchsite fluoresces lime green under long wave UV light. Fuchsite's radioactivity due to its potassium (K) content is barely detectable. Fuchsite Fuchsite, also known as chrome mica, is a chromium (Cr) rich variety of the mineral muscovite, belonging to the mica group of phyllosilicate minerals, with the following formula: K(Al,Cr)(AlSiO)(OH). Trivalent