... :7758-98-7The five-hydrate, also known as blue vitriol or blue vitriol. Copper sulfate pentahydrate Copper sulfate is also ... crystals.Appearance and properties: large granular dark blue granular crystal or crystalline powder blue. Toxic, odorless, with a metallic astringent ... of dyes and pigments such as copper single azo reactive blue, reactive violet. Industrial synthesis of organic spices and dyes ...