Descloizite Locality: Berg Aukas (Berg Aukus), Grootfontein District, Otjozondjupa Region, Namibia (Locality at mindat.org) A really showy rosette of radiating — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Descloizite
A lead-zinc vanadate of the oxidized zone — orthorhombic, isomorphous with olivenite, and prized as well-formed brown crystals.
Intro adapted from Wikipedia (CC BY-SA).
Descloizite is an IMA-recognized mineral species in the vanadate class, with the chemical formula PbZn(VO₄)(OH).
It crystallizes in the orthorhombic crystal system (space group P2_12_12_1). It is a member of the Descloizite structural group.
Key properties: Mohs hardness 3.5; specific gravity 6.2; typically brown or black or red or orange; Orange to brownish red streak; Greasy luster; refractive index 2.267; optically biaxial.
IMA symbol Dcz, grandfathered status — known before the IMA’s founding, named in 1854.
Found as a secondary mineral in the oxidized zone of vanadium-bearing base metal deposits; rarely an ore of vanadium.
It is found associated with Mottramite, vanadinite, pyromorphite, mimetite, wulfenite, cerussite.
The mineral was named to honor Alfred Lewis Oliver Legrand Des Cloizeaux (1817–1897), Professor of Mineralogy, University of Paris, Paris, France, who first described the mineral.
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