Yellowish crystals of changoite associated to hexagonal colorless caracolite in an aesthetic combination. From: Caracoles, Antofagasta Region, Chile. — Photo: David Hospital · CC BY-SA 4.0
Changoite
A rare hydrated sodium-zinc sulfate from Chile's San Francisco mine — the zinc analogue of blödite.
Intro adapted from Wikipedia (CC BY-SA).
Changoite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Na₂Zn(SO₄)₂·4H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/a). It is a member of the Blödite structural group.
Key properties: Mohs hardness 2–3; specific gravity 2.5; White streak; Vitreous luster; optically biaxial.
IMA symbol Cgo, IMA status: approved, named in 1997.
Found as a secondary mineral in the oxidized portion of a Cu–Zn sulfide deposit.
It is found associated with Thénardite, zincian paratacamite, gypsum.
The name refers to the Changos, early inhabitants of Chile.