Potash alum is a chemical compound with the formula KAl(SO₄)₂·12H₂O. It is a type of double sulfate salt that contains potassium, aluminum, and sulfate ions. Potash alum is commonly found in crystalline form and is known for its colorless or white appearance. It is soluble in water and has various applications in industries such as food processing, water purification, and cosmetics. In addition to its industrial uses, potash alum has a long history in traditional practices. It has been used in pickling and as a food preservative due to its antimicrobial properties. Furthermore, potash alum is sometimes utilized in dyeing and as a coagulant in water treatment processes, helping to clarify water by removing impurities.