Russellite
Yellow globular aggregates of the rare tungsten mineral russellite from the famous Clara Mine (Wolfach, Black Forest, Baden-Württemberg, Germany).
General
CategoryTungstate minerals
Formula
(repeating unit)
Bi2WO6
IMA symbolRll[1]
Strunz classification4.DE.15
Crystal systemOrthorhombic
Crystal classPyramidal (mm2)
H-M symbol: (mm2)
Space groupPca21
Unit cella = 5.43 Å, b = 16.43 Å
c = 5.45 Å; Z = 4
Identification
ColorYellow-green, yellow
Crystal habitFine-grained, compact, massive
Mohs scale hardness3.5
Specific gravity7.33 - 7.37
Optical propertiesBiaxial (+)
Refractive index2.17 - 2.51
Dispersionrelatively strong
References[2][3][4]

Russellite is a bismuth tungstate mineral with the chemical formula Bi2WO6.[2] It crystallizes in the orthorhombic crystal system. Russellite is yellow or yellow-green in color, with a Mohs hardness of 3+12.[2]

Russellite is named for the mineralogist Sir Arthur Russell, and the type locality is the Castle-an-Dinas Mine,[2] near St Columb Major in Cornwall, where it was found in 1938 in wolframite.[5] It occurs as a secondary alteration of other bismuth bearing minerals in tin - tungsten hydrothermal ore deposits, pegmatites and greisens. It typically occurs associated with native bismuth, bismuthinite, bismite, wolframite, ferberite, scheelite, ferritungstite, anthoinite, mpororoite, koechlinite, cassiterite, topaz, muscovite, tourmaline and quartz.[3]

References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. 1 2 3 4 Russellite: Russellite data on Mindat.org
  3. 1 2 Handbook of Mineralogy
  4. Webmineral data
  5. Embrey, P. G.; Symes, R. F. (1987). "The Mines and Mining". Minerals of Cornwall and Devon. London: British Museum (Natural History). p. 54. ISBN 0-565-00989-3.


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