Potassium sulfate (arcanite) is a white crystalline salt that is highly soluble in water. The salt exists naturally together with other sulfates of sodium, calcium and magnesium. It is important to note that the salt does not exist naturally on its own. Arcanite is produced industrially by reacting potassium chloride with sulfuric acid in what is known today as the Leblanc process. The by-products are hydrochloric acid and potassium sulphate. The salt, arcanite, is commonly used as a fertilizer. It's often used to grow fruits, vegetables and tobacco, which can be harmed by chlorine. The fertilizer supplies both sulfur and potassium, which help to ensure optimal growth of these plants. Another common use of arcanite is soda blasting. The salt is used as a substitute for soda since it is both hard and water-soluble. The crude form of the salt is sometimes used in the manufacturing of glass.