CALCITE is a carbonate of lime (CaCo3). It crystallizes in rhombohedron class. It is also known by the name calc-spar. It is white in colour but is also found in various shades like pink, brown etc., depending upon the impurities present. It is identified easily from other lime minerals by its well defined rhombohdral cleavage and hardness 3 of Moh's scale. Its composition is identical to that of limestone but the latter occurs as sedimentary beds. There is another mineral, aragonite, of the same chemical composition. It crystallizes in orthorhombic system. It is, however, an unstable mineral, found mainly associated with gypsum beds and the tests of reef-building corals. It is not found in the same large quantity as that of calcite.
