Conichalcite is a scarce calcium copper hydroxy-arsenate mineral (CaCu(AsO4)(OH)). It occurs in the altered (oxidized) zones of copper deposits that have arsenic-bearing minerals. Conichalcite has a nonmetallic luster, greenish color & streak, is somewhat hard (H = 4.5), is somewhat heavy for its size (due to the copper content), and has no cleavage. It typically forms crusts of small, fibrous- to needle-shaped crystals, or forms botryoidal masses.
Conichalcite from the Higgens Mine near Bisbee, Cochise County, southeastern Arizona, USA (CSM # 50611, Colorado School of Mines Geology Museum, Golden, Colorado, USA).