Decahydrate refers to a chemical compound that contains ten molecules of water (H₂O) for each molecule of the substance. This term is often used in the context of hydrates, which are compounds that include water in their crystalline structure. Decahydrates are commonly found in various salts and minerals, where the water molecules are integral to the compound's stability and properties. One well-known example of a decahydrate is copper(II) sulfate decahydrate, which is often used in laboratories and agriculture. In its hydrated form, it appears as bright blue crystals, and the water content can be removed through heating, resulting in anhydrous copper(II) sulfate.