Otwayite

(repeating unit)Ni2CO3(OH)2IMA symbolOtw[1]Strunz classification5.DA.15Crystal systemOrthorhombic
Unknown space groupUnit cella = 10.18, b = 27.4, c = 3.22 [Å]; Z = 8IdentificationColorBright greenCrystal habitSprays of Fibrous bundles oriented perpendicular to veinlet walls; spherules and claylike coatingsMohs scale hardness4LusterSilky to waxyDiaphaneityOpaque to translucentSpecific gravity3.41Optical propertiesBiaxialRefractive indexnα = 1.650 nγ = 1.720Birefringenceδ = 0.070PleochroismWeakDispersionVery strongReferences[2][3]

Otwayite, Ni2CO3(OH)2, is a hydrated nickel carbonate mineral. Otwayite is green, with a hardness of 4, a specific gravity of 3.4, and crystallises in the orthorhombic system.

Occurrence

Otwayite is found in association with nullaginite and hellyerite in the Otway nickel deposit. It is found in association with theoprastite, hellyerite, gaspeite and a suite of other nickel carbonate minerals in the Lord Brassey Mine, Tasmania. Otwayite is found in association with gaspeite, hellyerite and kambaldaite in the Widgie Townsite nickel gossan, Widgiemooltha, Western Australia. It is also reported from the Pafuri nickel deposit, South Africa. It was first described in 1977 from the Otway Nickel Deposit, Nullagine, Pilbara Craton, Western Australia and named for Australian prospector Charles Albert Otway (born 1922).[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. ^ Mindat.org
  3. ^ a b Handbook of Mineralogy
  • Nickel, E. H.; Robinson, B. W.; Davis, C. E. S.; MacDonald, R. D. (1977). "Otwayite, a new nickel mineral from Western Australia" (PDF). American Mineralogist. 62: 999–1002.
  • Nickel, E. H.; Hallbert, J. A.; Halligan, R. (1979). "Unusual nickel mineralization at Nullagine, Western Australia". Journal of the Geological Society of Australia. 26 (1–2): 61–71. Bibcode:1979AuJES..26...61N. doi:10.1080/00167617908729067.
  • Henry, D. A. & Birch, W. D. (1992): Otwayite and theophrastite from the Lord Brassey Mine, Tasmania. Mineral. Mag. 56, 252-255.
  • Andersen, P., Bottrill, R. & Davidson, P. (2002): Famous mineral localities: The Lord Brassey mine, Tasmania. Mineral. Rec. 33, 321-332.
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