Ceruleite is a hydrous copper aluminum hydroxy-arsenate mineral, Cu2Al7(AsO4)4(OH)1312H2O.  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).



Photo gallery of ceruleite



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