It is made by treating copper metal with hot sulfuric acid. Also can be made by slowly leaching low grade copper in the air. It is usually 98% pure copper sulfate and may contain water. It reacts with concentrated hydrochloric acid to make tetrachlorocuprate. Also reacts with reducing metals to make copper metal and the corresponding oxidizing material. It is used as a fungicide for grapes, melons and other sorts of berries. Also used to control invasive aquatic plants and in swimming pools as an algicide. It can be used in book binding pastes to prevent bug bites in pages. It was once used to fight off malaria.