Anhydrous copper sulfate is a chemical compound with the formula CuSO4. It appears as a white or light blue powder and is known for its hygroscopic properties, meaning it can absorb moisture from the air. This compound is commonly used in various applications, including agriculture as a fungicide and in laboratories for chemical experiments. When anhydrous copper sulfate absorbs water, it transforms into copper(II) sulfate pentahydrate, which is a blue crystalline solid. This transition is often used in educational demonstrations to illustrate chemical reactions and changes in physical states. Anhydrous copper sulfate is also utilized in the production of other copper compounds and in the manufacturing of certain dyes.