Anthonyite is a hydrous secondary copper halide mineral of Cu(OH,Cl)2•3(H2O).
It was discovered in 1963 in the Centennial mine, Calumet , Houghton County , United States. It was discovered by the University of Arizona mineralogist (1920–1992), who named it for himself.
Anthonyite is lavender in color, has a Mohs hardness of 2 and crystallizes in the monoclinic.
Anthonyite occurs as an alteration of native copper in basalt in fractures and cavities by circulation of chloride rich groundwater or connate mineral calumetite occurs by the same process. It occurs associated with tremolite , monazite and paratacamite in the Centennial mine area. It also occurs in the Cole mine, at Bisbee , Cochise County, Arizona, Sonora mineral in Richelsdorf, Greece