Typically sourced from Kazakhstan (Altyn-Tyube, the type locality),
the Democratic Republic of Congo, and Namibia, this mineral forms in
the oxidation zone (gossan) of copper deposits, through secondary
low-temperature alteration of primary copper sulfides in the presence
of silica. It crystallizes as short prisms terminated by rhombohedra,
with a characteristic intense emerald-green color caused by copper in
the lattice. Hardness 5 Mohs, density 3.28–3.35 g/cm³, perfect cleavage, brittle.
n extremely sought-after
collector’s stone for the intensity of its green color , often compared to
emerald; rarely faceted for jewelry due to its brittleness and perfect
cleavage; a highly prized specimen for specialized mineralogical
collections.