Natural calcite is a common form of calcium carbonate (CaCO3), is white given to its purity. More impurities in the calcite, more it will appear in any other color, for instance green, pink, red, yellow, blue, brown or black. With a specific gravity of 2.71, molecular weight of 100.09 (g/mol.), 9.3 to 9.8 pH, and Mohs hardness of 3, natural calcite is 98% to 99.9% pure. A lot of industries demand CaCO3, for instance pharmaceutical, rubber, ink, plastic, glass, chemical, paint, food, etc. This comes in food grade, pharmaceutical grade and industrial grade, and companies based on their industrial sector can select the most appropriate.