This substance can be found in a few different forms, depending on its composition. The most common type of copper sulfate is the pentahydrate substance, which forms a bright blue, crystalline solid. Other names for this material include blue vitriol or bluestone. There are other hydrous forms of copper sulfate, and its most basic form it is a white powder. The primary application of copper sulfate is a fungicide. The substance binds to the proteins in most fungi and algae, causing the cells to leak and die. Garden snails are also killed by copper sulfate, so it can be employed for that purpose as well. Because of its blue coloring, the pentahydrate of copper sulfate can also be used as a dye for various applications. This substance is somewhat toxic to humans, so gloves and goggles should be worn when handling it. It is stable in the air and non-flammable, but it can irritate the skin. Copper sulfate can also be hazardous if swallowed.