Copper sulfate has the chemical formula Cu2SO4. It is an inorganic compound used as a pesticide to kill bacteria, algae, snails and fungi. It is also used for recreational crystal growing.
As a pesticide, copper sulfate binds to proteins in bacteria, fungi and algae and kills them. It kills snails by interfering with skin cells and enzymes. To grow blue crystals, copper sulfate is dissolved in hot water and placed in a clean jar with a seed crystal hanging in the middle. However, this copper sulfate is toxic and can cause eye irritation, nausea and damage body tissues, including the liver, kidneys and blood cells depending on the extent of exposure. Caution is needed while using copper sulfate as a pesticide or to grow crystals.