Potassium sulfate (K2SO4)is a colorless compound having rhombic or hexagonal crystals. It readily forms double salts with the sulfate of trivalent metals, which are known as Alums. It also forms double salts with calcium, magnesium and sodium sulfates. It is widely employed as a fertilizer. K2SO4 can be extracted from various complex salts in nature, such as Kainite, langbeinite and carpathein mineral ores. It can be synthesized by reacting KCl and sulfuric acid, via Mannheim process.