The chemical formula of strontium sulfate SrSO4. Orthorhombic crystal system, the crystal is in the form of plate, short column or spindle. Colorless or light blue, sometimes light green, light yellow, light red or white. The glass is glossy and streaked white. It is insoluble in water. Strontium sulfate is generally used to prepare self-regulating chromium plating solution to control the content of chloride ion and free sulfate ion. Strontium sulfate can be prepared by celestite purification method.