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Wooldridgeite, Na2(P2O7)2(H2O)10: A new mineral from Judkins Quarry, Warwickshire, England

Published online by Cambridge University Press:  05 July 2018

F. C. Hawthorne ,
M. A. Cooper ,
D. I. Green ,
R. E. Starkey ,
A. C. Roberts  and
J. D. Grice
F. C. Hawthorne
Affiliation:
Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
M. A. Cooper
Affiliation:
Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
D. I. Green
Affiliation:
The Manchester Museum, University of Manchester, Oxford Road, Manchester M13 9PL, UK
R. E. Starkey
Affiliation:
15 Warwick Avenue, Bromsgrove, Worcestershire B60 2AH, UK
A. C. Roberts
Affiliation:
Geological Survery of Canada, 601 Booth Street, Ottawa, Ontario, Canada K1A 0E8
J. D. Grice
Affiliation:
Research Division, Canadian Museum of Nature, PO Box 3443, Station D, Ottawa, Ontario, Canada K1P 6P4
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Abstract

Wooldridgeite, ideally Na2(P2O7)2(H2O)10, orthorhombic, a = 11.938(1), b = 32.854(2), c = 11.017(1) Å , V = 4321.2(8) Å3, a:b:c = 0.3634:1:0.3353, space group Fdd2, Z = 8, is a new mineral from Judkins Quarry, Nuneaton, Warwickshire, England. Associated minerals are calcite, chalcopyrite, bornite and baryte. It occurs as equant crystals forming rhombic dipyramids; no twinning was observed. It is transparent blue-green with a very pale-blue streak, a vitreous lustre, and does not fluoresce under long- or short-wave ultraviolet light. Wooldridgeite has a Mohs hardness of 2–3, is brittle with an irregular fracture, and has no cleavage. The calculated density is 2.279 g/cm3. In transmitted light, wooldridgeite is colourless, non-pleochroic, and shows no dispersion. It is biaxial negative with α = 1.508(1), β = 1.511(1), γ = 1.517(1), 2V(meas.) = 76.2(5), 2V(calc.) = 71(10)8, X = b, Y = c, Z = a. The strongest five reflections in the X-ray powder diffraction pattern are [d(Å), (I), (hkl)]: 8.23(30)(040), 6.52(100)(131), 4.05(40)(260), 3.255(40)(262); 2.924(40)(371). Electron-microprobe analysis of wooldridgeite gave P2O5 39.37, CuO 20.24, MgO 0.24, CaO 7.73, Na2O 8.33, K2O 0.17, H2O(calc.) 24.72, sum 100.80 wt.%; the corresponding unit formula (based on 24 anions) is (Na1.96K0.03)Ca1.00(Cu1.85Mg0.04)P4.04O14(H2O)10 where the H2O groups were assigned from knowledge of the crystal structure; the infrared absorption spectrum also indicates the presence of H2O in the structure. The mineral is named for James Wooldridge (1923–1995), a fervent amateur mineral collector who discovered this mineral.

Keywords

wooldrigeitenew mineralpyrophosphateJudkins QuarryWarwickshireEngland
Type
Research Article
Information
Mineralogical Magazine , Volume 63 , Issue 1 , February 1999 , pp. 13 - 16
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1999

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References

Cooper, M.A. and Hawthorne, F.C. (1998) The crystal structure of wooldridgeite, Na2CaCu2 2+ (P2O7)2(H2O)10, a novel pyrophosphate structure. Canad. Mineral. (submitted).Google Scholar
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