Copper sulfate, also known as ”blue stone” or ”blue vitriol”, is a chemical compound, used in a wide range of industries. The basic chemical formula of copper sulfate is ”CuSO4”, but the salt exists as a series of different compounds, depending on the degree of hydration. ”Chalcocite”, the anhydrous form of copper sulfate, occurs as a rare mineral and exists as pale green or grayish white powder.