Volborthite
3+1⁄2Luster Vitreous, waxy, greasy, pearly Streak light green Diaphaneity Translucent Specific gravity 3.5 - 3.8 Optical properties Biaxial (+/-) Refractive index nα = 1.793 nβ = 1.801 nγ = 1.816 Birefringence δ = 0.023 Pleochroism Weak 2V angle Measured: 63° to 83° Dispersion Translucent to Subtranslucent Ultraviolet fluorescence Non-fluorescent Solubility Soluble in acids References [2][3][4]
Volborthite is a mineral containing copper and vanadium, with the formula Cu3V2O7(OH)2·2H2O. Found originally in 1838 in the Urals, it was first named knaufite but was later changed to volborthite for Alexander von Volborth (1800–1876), a Russian paleontologist.[5]
Tangeite (synonym: calciovolborthite), CaCuVO4(OH), is closely related.
Occurrence
Volborthite was first described in 1837 for an occurrence in the Sofronovskii Mine, Yugovskii Zavod, Perm, Permskaya Oblast, Middle Urals, Russia.[3]
It occurs as an uncommon oxidation mineral in vanadium bearing hydrothermal copper ores. It is associated with brochantite, malachite, atacamite, tangeite, chrysocolla, baryte and gypsum.[2]
References
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