Sharp green crystals of the new mineral paratacamite-(Mg) (IMA 2013-014). Paratacamite-(Mg) is a Cu-Mg hydroxylchloride mineral found only in this locality worldwide (Cuya, Los Camarones, Arica Province, Arica & Parinacota Region, Chile), where it is very rare. — Photo: David Hospital · CC BY-SA 4.0
Paratacamite-(Mg)
Paratacamite-(Mg) is an IMA-recognized mineral species in the halide class, with the chemical formula Cu₃(Mg,Cu)Cl₂(OH)₆.
It crystallizes in the hexagonal crystal system (space group R-3). It is a member of the Atacamite structural group.
Key properties: Mohs hardness 3–3.5; specific gravity 3.5; Light green streak; Vitreous luster; optically uniaxial.
IMA symbol Pata-Mg, IMA status: approved, named in 2013.
Found as a secondary mineral in near-surface, low-temperature, oxidation zones under increasingly arid conditions.
It is found associated with Anhydrite, atacamite, chalcopyrite, copiapite, dolomite, epsomite, haydeeite, hematite, magnesite, quartz.
As the magnesium analogue of paratacamite.