Ball-and-stick model of the unit cell of the mineral liroconite, Cu2Al(AsO4)(OH)4·4(H2O), from the crystal structure determined by single-crystal X-ray diffrac — Photo: Ben Mills · Public domain
Liroconite
A vitreous blue-to-green hydrated copper-aluminium arsenate — among the most beautiful secondary copper minerals.
Intro adapted from Wikipedia (CC BY-SA).
Liroconite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Cu₂Al(AsO₄)(OH)₄·4H₂O.
It crystallizes in the monoclinic crystal system (space group I2/a). It is a member of the Liroconite structural group.
Key properties: Mohs hardness 2–2.5; specific gravity 2.94–3.01; typically blue or green; Pale blue to pale green streak; Vitreous to resinous luster; refractive index 1.646; optically biaxial.
IMA symbol Lro, grandfathered status — known before the IMA’s founding, named in 1822.
A rare secondary mineral found in the oxidized zone of some copper deposits.
It is found associated with Olivenite, chalcophyllite, clinoclase, cornwallite, strashimirite, malachite, cuprite, “limonite”.
Its name comes from the Greek for pale and powder, for its pale blue to green streak.
Collections: Collector Favorites, Rare & Remarkable.