Importance of Water in Gypsum

Gypsum's chemical formula is CaSO₄·2H₂O, which means it contains two water molecules. These water molecules are known as water of crystallization. They are integral to the crystal structure of gypsum and help in maintaining its form and stability. Without these water molecules, gypsum would lose its crystalline structure and convert to anhydrite (CaSO₄), which is an anhydrous form of calcium sulfate.