CERULEITE
Ceruleite is a hydrous copper aluminum
hydroxy-arsenate mineral, Cu2Al7(AsO4)4(OH)13·12H2O.
It has a nonmetallic luster, a rich blue color, a pale bluish streak, is
moderately hard (H = 5 to 6), and is typically massive, compact, or
powdery. Ceruleite is only known in the oxidized zone of arsenic-bearing
metallic mineral deposits.
Ceruleite from the Emma Louisa Mine, Guanaco District, Antofagasta Province,
Chile (CSM # 52600, Colorado School of Mines Geology Museum, Golden, Colorado,
USA).