Langite

IMA formula: Cu₄(SO₄)(OH)₆·2H₂O

Crystallography: Monoclinic. Pc. a = 7.1026(2)  Å, b = 6.0143(1)  Å, c = 11.1645(3)  Å, β = 90.1103(8)°. Z = 2.