Volborthite

Cu3 V2 O7 (OH)2 • 2H2 O
c 2001-2005 Mineral Data Publishing, version 1

Crystal Data: Monoclinic, pseudohexagonal. Point Group: 2/m. Typically as rosettelike
aggregates of scaly crystals, which may have a hexagonal or triangular outline, to 5 mm.
Physical Properties:D(calc.) = 3.52

Cleavage: One, perfect. Hardness = 3.5

D(meas.) = 3.5–3.8

Optical Properties: Semitransparent. Color: Dark olive-green, green, yellowish green; green
to yellowish green in transmitted light. Luster: Vitreous, oily, resinous, waxy, pearly on thecleavage.
Optical Class: Biaxial (–) or biaxial (+). Pleochroism: Faint. Dispersion: r < v, r > v,inclined. α = 1.820–2.01 β = 1.835–2.05 γ = 1.92–2.07 2V(meas.) = 63◦ –83◦
Cell Data: Space Group: C2/m. a = 10.610(2)β = 95.04(2)◦ Z = 2b = 5.866(1)c = 7.208(1)

X-ray Powder Pattern: Monument No. 1 mine, Arizona, USA.
7.16 (10), 2.643 (7), 2.571 (7), 2.389 (7), 4.103 (5), 3.090 (5), 2.998 (5)Chemistry:
V2 O5
SiO2
V2 O3(1)
36.65
1.37
1.70

(2)
38.32

CuO
H2 O(1)
48.79[11.49]

(2)
50.29
11.39

Total [100.00]
100.00(1) Scrava mine, Italy; by electron microprobe; V2 O3 assumed for charge balance, H2 O by
5+3+difference; corresponds to Cu2.89 V1.90
V0.11
Si0.11 O7 (OH)2 • 2H2 O. (2) Cu3 V2 O7 (OH)2 • 2H2 O.
Occurrence: An uncommon secondary mineral in the oxidized zone of vanadium-bearinghydrothermal mineral deposits.
Association:Brochantite, malachite, atacamite, tangeite, chrysocolla, barite, gypsum.

Distribution: In Russia, originally from an unknown locality; later identified at theSofronovskii copper mine, near Perm, and at Syssersk and Nizhni Tagil, Ural Mountains. InUzbekistan, in the Hodzha-Akhmet quarry, near Uch-Kuduk, Kyzylkum desert. From theUzbekistana district, Fergana Valley, Alai Range, Kyrgyzstan. In the Scrava mine, Val Graveglia,Liguria, Italy. At the Blaby mine, Glen Parva, Leistershire, England. From Ronneburg, Thuringia,Germany. In the USA, at the Tennessee Queen mine, Richardson, near Thompson, Grand Co.,and elsewhere in Utah; in the Radium No. 5 mine, San Juan No. 3 mine, and Cougar mine,
Slick Rock district, San Miguel Co., and probably elsewhere in Colorado; from the Gold Quarrymine, near Carlin, Maggie Creek district, and in the Carlin mine, 50 km northwest of Elko, Lynndistrict, Eureka Co., Nevada; at the Monument No. 1 mine, Monument Valley, Navajo Co.,
Arizona; in the Green Monster mine, Inyo Co., California. At Menzies Bay, Vancouver Island,British Columbia, Canada. From the Luiswishi copper mine, Lubumbashi, Katanga Province,Congo (Shaba Province, Zaire). At Uris-Bobos, Namibia. There are additional minor localities.
Name: To honor Aleksandr Fedorovich von Volborth (1800–1876), Russian paleontologist, who
first noticed the mineral.
References: (1) Palache, C., H. Berman, and C. Frondel (1951) Dana’s system of mineralogy,(7th edition), v. II, 818–819. (2) Leonardsen, E.S. and O.V. Petersen (1974) The unit cell ofvolborthite. Amer. Mineral., 59, 372–373. (3) Basso, R., A. Palenzona, and L. Zefiro (1988)
Crystal structure refinement of volborthite from Scrava mine (Eastern Liguria, Italy). Neues
Jahrb. Mineral., Monatsh., 385–394. (4) Lafontaine, M.A., A. Le Bail, and G. Férey (1990)
Copper-containing minerals – I. Cu3 V2 O7 (OH)2 , 2H2 O: the synthetic homolog of volborthite;
crystal structure determination from X-ray and neutron data; structural correlations. J. SolidState Chem., 85, 220–227. (5) Pekov, I.V. (1998) Minerals first discovered on the territory of theformer Soviet Union, 231–232.
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