Volborthite Locality: Sofronovskii Cu Mine, Yugovskii Zavod, Perm', Permskaya Oblast', Middle Urals, Urals Region, Russia (Locality at mindat.org) This is a rar — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Volborthite
A copper vanadate described in 1838 from the Urals — the namesake of the volborthite group.
Intro adapted from Wikipedia (CC BY-SA).
Volborthite is an IMA-recognized mineral species in the vanadate class, with the chemical formula Cu₃V₂O₇(OH)₂·2H₂O.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Volborthite structural group.
Key properties: Mohs hardness 3.5; specific gravity 3.5–3.8; typically green; white streak; Vitreous, oily, resinous, waxy, pearly on the cleavage luster; refractive index 1.803; optically biaxial.
IMA symbol Vbo, IMA status: approved, named in 1838.
Occurs as an uncommon secondary mineral in the oxidized zone of vanadium-bearing hydrothermal mineral deposits.
It is found associated with Brochantite, malachite, atacamite, tangeite, chrysocolla, barite, gypsum.
The mineral was named to honor Aleksandr Fedorovich von Volborth (1800–1876), Russian paleontologist, who first noticed the mineral.
Collections: Collector Favorites, Rare & Remarkable.