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Grguricite, CaCr2(CO3)2(OH)4.4H2O, a new alumohydrocalcite analogue

Published online by Cambridge University Press:  01 September 2020

Michael S. Rumsey Open the ORCID record for Michael S. Rumsey [Opens in a new window] ,
Mark D. Welch ,
John Spratt  and
Annette K. Kleppe
Michael S. Rumsey*
Affiliation:
Department of Earth Sciences, Natural History Museum, London, United KingdomSW7 5BD
Mark D. Welch
Affiliation:
Department of Earth Sciences, Natural History Museum, London, United KingdomSW7 5BD
John Spratt
Affiliation:
Core Research Laboratories, Natural History Museum, London, United KingdomSW7 5BD
Annette K. Kleppe
Affiliation:
Diamond Light Source Ltd, Didcot, Oxfordshire, United KingdomOX11 0DE.
*
*Author for correspondence: Michael S. Rumsey, Email: m.rumsey@nhm.ac.uk
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Abstract

The occurrence and characterisation of a new member of the dundasite group are reported. Grguricite, ideally CaCr2(CO3)2(OH)4⋅4H2O, is the Cr analogue of alumohydrocalcite, CaAl2(CO3)2(OH)4⋅4H2O and occurs as lilac crusts of very fine-grained crystalline aggregates in the Pb–Ba–V mineralisation found at the Adeghoual Mine, Mibladen, Morocco (32°46′0″N, 4°37′59″W). The identification was based upon a close match with the powder X-ray diffraction data for alumohydrocalcite, the confirmation of anion components identified by Raman spectroscopy and the cation composition determined by electron-probe microanalysis. The empirical formula based upon 14 oxygen atoms per formula unit is Ca0.84Pb0.03Cr1.65Al0.39Mg0.02(CO3)2(OH)4⋅4H2O, with carbonate, hydroxyl and water contents set to those of the alumohydrocalcite stoichiometry. The fine-grained nature of the crystals (c. 0.5 μm × 0.1 μm × 5 μm) precluded a single-crystal X-ray study and both density and optical determinations. Grguricite is triclinic with space group P${\bar 1}$. Unit-cell parameters refined from the powder diffraction data are: a = 5.724(2), b = 6.5304(9), c = 14.646(4) Å, α = 81.682(1), β = 83.712(2), γ = 86.365(2)°, V = 537.8(2) Å3 and Z = 2. The five strongest peaks in the powder pattern are [dhkl, Å (I/Imax)(hkl)]: 6.222(100)(011), 3.227(87)(020), 6.454(63)(010), 2.883(58)(005, 023, 121) and 7.208(45)(002). The mineral is named after Australian geologist Ben Grguric.

Keywords

new mineralgrguricitealumohydrocalcitedundasite groupdresseritecalcium chromium carbonate hydroxide hydrate
Type
Article
Information
Mineralogical Magazine , Volume 84 , Issue 5 , October 2020 , pp. 778 - 784
Copyright
Copyright © The Author(s), 2020. Published by Cambridge University Press on behalf of The Mineralogical Society of Great Britain and Ireland

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Footnotes

Associate Editor: Anthony R Kampf

References

Birch, W.D., Kolitsch, U., Witzke, T., Nasdala, L. and Bottrill, R.S. (2000) Petterdite, the Cr-dominant analog of dundasite, a new mineral species from Dundas, Tasmania, Australia and Callenberg, Saxony, Germany. The Canadian Mineralogist, 38, 1467–1476.CrossRefGoogle Scholar
Clark, C., Grguric, B. and Mumm, A.S. (2004) Genetic implications of pyrite chemistry from the Palaeoproterozoic Olary Domain and overlying Neoproterozoic Adelaidean sequences, northeastern South Australia. Ore Geology Reviews, 25, 237–257.CrossRefGoogle Scholar
Cocco, G., Fansani, L., Nunzi, A. and Zanazzi, P.F. (1972) The crystal structure of dundasite. Mineralogical Magazine, 38, 564–569.CrossRefGoogle Scholar
Degen, T., Sadki, M., Bron, E., König, U. and Néner, G. (2014) The HighScore suite. Powder Diffraction, 29 (Supplement 2), S13–S18.CrossRefGoogle Scholar
Grguric, B.A., Madsen, I.C. and Pring, A. (2001) Woodallite, a new chromium analogue of iowaite from the Mount Keith nickel deposit, Western Australia. Mineralogical Magazine, 65, 427–435.CrossRefGoogle Scholar
Grguric, B.A. (2002) Hypogene violarite of exsolution origin from Mount Keith, Western Australia: field evidence for a stable pentlandite–violarite tie line. Mineralogical Magazine, 66, 313–326.CrossRefGoogle Scholar
Grguric, B.A., Pring, A., Bevan, A.W.R. and Downes, P.J. (2006) The minerals of Comet Vale, Western Australia. Australian Journal of Mineralogy, 12, 9–23.Google Scholar
Grguric, B.A., Seat, Z., Karpuzov, A.A. and Simonov, O.N. (2013) The West Jordan deposit, a newly-discovered type 2 dunite-hosted nickel sulphide system in the northern Agnew–Wiluna belt, Western Australia. Ore Geology Reviews, 51, 79–92.CrossRefGoogle Scholar
Jambor, J.L., Fong, D.G. and Sabina, A.P. (1969) Dresserite, the new barium analogue of dundasite. The Canadian Mineralogist, 10, 84–89.Google Scholar
Jambor, J.L., Sabina, A.P., and Sturman, B.D. (1977) Hydrodresserite, a new Ba-Al carbonate from a silicocarbonatite sill, Montreal Island, Quebec. The Canadian Mineralogist, 15, 399–404.Google Scholar
Praszkier, T. (2013) Mibladen, Morocco. Mineralogical Record, 44, 247–285.Google Scholar
Rumsey, M.S., Welch, M.D., Spratt, J. and Kleppe, A. (2020) Grguricite, IMA 2019-123. CNMNC Newsletter No. 54. Mineralogical Magazine, 84, 359–365.Google Scholar
Sajó, I.E. and Szakáll, S. (2007) Kochsándorite, a new Ca-Al carbonate mineral species from the Mány coal deposit, Hungary. The Canadian Mineralogist, 45, 479–483.CrossRefGoogle Scholar
Scheetz, E.B. and White, B.W. (1977) Vibrational spectra of the alkaline earth double carbonates. American Mineralogist, 62, 36–50.Google Scholar
Stachowicz, M., Parafiniuk, J., Wilson, C., Coles, S. and Woźniak, K. (2015) Applications of Hirshfeld surfaces to mineralogy: An example of alumohydrocalcite, and the classification of the dundasite group minerals. American Mineralogist, 100, 110–119.CrossRefGoogle Scholar
Szymański, J.T. (1982) The crystal structure of hydrodresserite, BaAl2(CO3)2(OH)4⋅3H2O. The Canadian Mineralogist, 20, 253–262.Google Scholar
Whitfield, P.S., Mitchell, L.D., Le Page, Y., Margeson, J. and Roberts, A.C. (2010) Crystal structure of the mineral strontiodresserite from laboratory powder diffraction. Powder Diffraction, 25, 322–328.CrossRefGoogle Scholar