Chalcoalumite is a hydrous copper aluminum hydroxy-sulfate mineral (CuAl4SO4(OH)123H2O).  It's a secondary mineral, forming in the altered (oxidized) zone of copper deposits.  It has a nonmetallic luster, a greenish to bluish color, a whitish to bluish-white streak, and is fairly soft (H = 2.5).  Chalcoalumite forms moderately thin crusts of tiny fibers.  Fragments of chalcoalumite have been observed to be flexible (elastic).


Chalcoalumite (bluish) on limonite (yellowish-brown) from a copper mine near Bisbee, Cochise County, southeastern Arizona, USA



Photo gallery of chalcoalumite



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