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Redgillite, Cu6(OH)10(SO4)·H2O, a new mineral from Caldbeck Fells, Cumbria, England: description and crystal structure

  • J. J. Pluth (a1), I. M. Steele (a1), A. R. Kampf (a2) and D. I. Green (a3)

Abstract

Redgillite, Cu6(OH)10(SO4)·H2O, space group P21/c, a 3.155(3) Å, b 10.441(8) Å, c 19.436(16) Å, β 90.089(13)°, V = 640.2(9) Å3, Z = 2, is a new mineral from Silver Gill, Caldbeck Fells, Cumbria, England. The strongest six lines of the X-ray powder-diffraction pattern [d in Å, (I) (hkl)] are: 9.72 (90) (002), 7.11 (100) (012), 4.60 (30) (022), 4.068 (20) (023), 2.880 (30) (112,112̄), 2.318 (50) (131,131̄). It occurs as translucent to transparent grass-green bladed crystals up to 0.15 mm long with squared-off or tapering terminations; usually in radiating groups. Forms observed are {001} prominent, {010} as composite stepped faces, and {100} irregular. Redgillite has white streak, vitreous lustre and Mohs hardness of ∼2. Blades are slightly flexible with irregular fracture and exhibit a perfect {001} cleavage and good {100} and {010} cleavages. The measured density (by sink-float) is 3.45(5) g/cm3; the calculated density is 3.450 g/cm3. The mineral dissolves slowly in dilute HCl. Redgillite is biaxial- negative with α = 1.693(2), β = 1.721(2), γ = 1.723(2), 2V = 30(2)° (meas.) and 30° (calc.); dispersion is r > v, medium; pleochroism: Y blue-green α X blue-green α Z yellow-green; orientation: X ≈ c , Y = b, Z ≈ a. Electron microprobe analyses yielded CuO 68.9, SO3 11.6, total 80.5. With water inferred from the structure analysis, the empirical formula is: Cu5.995(OH)9.991(SO4)1.003·H2O. Redgillite is typically found in thin fractures in partly oxidized sulphides where it is commonly associated with langite and more rarely with malachite, cuprite, connellite and brochantite. The name is for the Red Gill mine, from which the mineral is best known. The crystal structure of redgillite was determined and refined to R = 0.090 for 1529 observed reflections [I > 2σ(I)]. The redgillite structure consists of Jahn-Teller distorted CuO6 octahedra and SO4 tetrahedra. The octahedra share edges to form sheets that are zig-zag in cross section. The SO4 tetrahedra share an oxygen with the Cu layer and link the layers by hydrogen bonds to OH groups. The crystal structures of wroewolfeite, langite, posnjakite, spangolite and schulenbergite are similar to redgillite. They all contain edge sharing CuO6 layers connected to SO4 groups with the layers bridged via hydrogen bonds.

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References

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Betterton, J. (2000) Famous Mineral Localities: Penberthy Croft Mine, St. Hilary, Cornwall England.. UK Journal of Mines & Minerals, 20, 7–37.
British Geological Survey (1997) Cockermouth. England and Wales, Sheet 23. Solid Geology. 1:50,000. British Geological Survey, Keyworth, Nottingham, UK.
Cooper, M.P. and Stanley, C.J (1990) Minerals of the English Lake District. Natural History Museum Publications, London.
Cooper, M.P. and Stanley, C.J. (1991) Famous mineral localities: pyromorphite group minerals from the Caldbeck Fells, Cumbria, England. Mineralogical Record, 22, 105–121.
Gentsch, M. and Weber, K. (1984) Structure of langite, Cu4[(OH)6|SO4].2H2O. Acta Crystallographica, C40, 1309–1311.
Hamada, E., Ishizawa, N., Marumo, F., Oshumi, K., Shimizugawa, Y., Reizen, K. and Matsumami, T. (1996) Structure of Mg6SO2(OH)14 determined by micro single-crystal X-ray diffraction. Acta Crystallographica, B52, 266–269.
Hawthorne, F.C. and Groat, L.A. (1985) The crystal structure of wroewolfeite, a mineral with [Cu4(OH)6(SO4)(H2O)] sheets. American Mineralogist, 70, 1050–1055.
Hawthorne, F.C., Kimata, M. and Eby, R.K. (1993) The crystal structure of spangolite, a complex copper sulfate sheet mineral. American Mineralogist, 78, 649–652.
Hawthorne, F.C., Krivovichev, S.V. and Burns, P.C. (2000) The crystal chemistry of sulfate minerals. Pp. 1112 in: Sulfate Minerals - Crystallography, Geochemistry, and Environmental Significance. Reviews in Mineralogy, 40. Mineralogical Society of America, Washington, D.C.
Mellini, M. and Merlino, S. (1979) Posnjakite: [Cu4(OH)6(H2O)O] octahedral sheets in its structure. Zeitschriftfür Kristallographie, 149, 249–257.
Mumme, W.G., Sarp, H. and Chiappero, P.J. (1994) A note on the crystal structure of schulenbergite. Archives des Sciences (Geneve), 47, 117—124.
Sheldrick, G.M. (1997) SHELXTL, a Program for Crystal Structure Refinement. Göttingen, Germany.
Willis, A.S. and Brown, I.D. (1999) VaList. CEA, France.

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Table 6. Atomic fractional coordinates (x 104), equivalent isotropic and anisotropic displacement coefficients of Sr feldspar (pdf 60 KB)

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Supplementary materials

Pluth et al. supplementary material
Table 7. Observed and calculated structure factors for Sr feldspar (pdf 372 KB)

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Redgillite, Cu6(OH)10(SO4)·H2O, a new mineral from Caldbeck Fells, Cumbria, England: description and crystal structure

  • J. J. Pluth (a1), I. M. Steele (a1), A. R. Kampf (a2) and D. I. Green (a3)

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