Exhibit in the University of Arizona Mineral Museum - University of Arizona - Tucson, Arizona, USA. — Photo: Daderot · CC0
Mottramite
Lead-copper vanadate — the copper end of the descloizite series, formerly called psittacinite.
Intro adapted from Wikipedia (CC BY-SA).
Mottramite is an IMA-recognized mineral species in the vanadate class, with the chemical formula PbCu(VO₄)(OH).
It crystallizes in the orthorhombic crystal system (space group Pnma). It is a member of the Descloizite structural group.
Key properties: Mohs hardness 3–3.5; specific gravity 5.9; typically green or brown or black; Yellowish green streak; Greasy luster; refractive index 2.129; optically biaxial.
IMA symbol Mott, grandfathered status — known before the IMA’s founding, named in 1876.
Found as a secondary mineral in the oxidized zone of vanadium-bearing base metal deposits.
It is found associated with Descloizite, duftite, mimetite, wulfenite, cerussite, azurite, dioptase.
The name refers to an occurrence in England, ore stockpiled at Mottram St. Andrew, Cheshire; likely mined from the nearby Pim Hill mine, Shrewsbury, Shropshire.
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