${\text{CuSO}}_4\cdot 5{\text{H}}_2\text{O}$ is called

Copper sulfate pentahydrate (${\text{CuSO}}_4\cdot 5{\text{H}}_2\text{O}$) is commonly known as blue vitriol due to its bright blue color. For reference, green vitriol is ferrous sulfate heptahydrate (${\text{FeSO}}_4\cdot 7{\text{H}}_2\text{O}$), white vitriol is zinc sulfate heptahydrate (${\text{ZnSO}}_4\cdot 7{\text{H}}_2\text{O}$), and gypsum is calcium sulfate dihydrate (${\text{CaSO}}_4\cdot 2{\text{H}}_2\text{O}$).