Hostname: page-component-586b7cd67f-g8jcs Total loading time: 0 Render date: 2024-11-25T01:47:55.132Z Has data issue: false hasContentIssue false
  • English
  • Français

Natropharmacoalumite, NaAl4[(OH)4(AsO4)3].4H2O, a new mineral of the pharmacosiderite supergroup and the renaming of aluminopharmacosiderite to pharmacoalumite

Published online by Cambridge University Press:  05 July 2018

M. S. Rumsey ,
S. J. Mills  and
J. Spratt
M. S. Rumsey*
Affiliation:
Department of Mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK
S. J. Mills
Affiliation:
Department of Earth and Ocean Sciences, University of British Columbia, Vancouver BC, Canada V6T 1Z4
J. Spratt
Affiliation:
Department of Mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK
*
*E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Natropharmacoalumite, ideally NaAl4[(OH)4(AsO4)3]·4H2O, is a new mineral from the Maria Josefa Gold mine, Rodalquilar, Andalusia region, Spain. It occurs as colourless, intergrown cubic crystals with chenevixite, kaolinite, jarosite and indeterminable mixtures of Fe and Sb oxyhydroxides. Individual crystals are up to 0.5 mm on edge, although crystals are more commonly ˜0.25 mm across and occur in patchy aggregates several millimetres across. The mineral is transparent with a vitreous to adamantine lustre. It is brittle with an imperfect cleavage, irregular fracture and a white streak. The Mohs hardness is ˜2.5 with a calculated densityof 2.56 g cm–3 for the empirical formula. Electron microprobe analyses yielded Na2O 2.52%, K2O 1.49%, Al2O3 29.50%, As2O5 48.84% and H2O was calculated in line with the structural analysis as 16.28% totalling 98.63%. The empirical formula, based upon 20.21 oxygen atoms, is [Na0.57K0.22(H3O)0.21]Σ1.00Al4.05(As2.97O12)(OH)4·4H2O. The five strongest lines in the X-ray powder diffraction pattern are [dobs(Å), Iobs,(hkl)]: 7.759,100,(100); 4.473,40,(111); 3.870,50,(200); 2.446,9,(301); 2.331,12,(311). Natropharmacoalumite is cubic, space group with a = 7.7280(3) Å, V = 461.53(3) Å3 and Z = 1. The crystal structure was solved by direct methods and refined to R1 = 0.063 for 295 reflections with F>4σ(F). The structure conforms broadly to that of the general pharmacosiderite structure type, with Na as the dominant cation in cavities of strongly distorted Al octahedra and As tetrahedra. A new group nomenclature system for minerals with the pharmacosiderite structure has been established, including the renaming of aluminopharmacosiderite to pharmacoalumite.

Keywords

natropharmacoalumitepharmacosiderite groupnew mineral speciessodium aluminium arsenateMaria Josefa mineRodalquilarSpainmineral nomenclatureredefinitionaluminopharmacosideritepharmacoalumite
Type
Research Article
Information
Mineralogical Magazine , Volume 74 , Issue 5 , October 2010 , pp. 929 - 936
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Anthony, J.W., Bideaux, R.A., Bladh, K.W. and Nichols, M.C. (2000) Handbook of Mineralogy, Volume IV, Arsenates, Phosphates, Vanadates. Mineral Data Publishing, Tucson, Arizona, USA.Google Scholar
Arribas, A. Jr., Cunningham, C.G., Rytube, J.J., Rye, R.O., Kelly, W.C., Podwysocki, M.H., McKee, E.H. and Toasdal, R.M. (1995) Geology, geochronology, and isotope geochemistry of the Rodalquilar gold-alunite deposit, Spain. Economic Geology, 90, 795–822.CrossRefGoogle Scholar
Bruker (2003) SAINT, SADABS and SHELXTL. Bruker AXS Inc., Madison, Wisconsin, USA.Google Scholar
Buerger, M.J., Dollase, W.A. and Garaycochea-Wittke, I. (1967) The structure and composition of the mineral pharmacosiderite. Zeitschrift für Kristallographie, 125, 92–108.CrossRefGoogle Scholar
Hatert, F. and Burke, E.A.J. (2008) The IMA-CNMNC dominant-constituent rule revisited and extended. The Canadian Mineralogist, 46, 717–728.CrossRefGoogle Scholar
Hausmann, J.F.L. (1813) Handbuch der Mineralogie. 3 volumes, Göttingen, 1065 (as Pharmakosiderit).Google Scholar
Mills, S.J., Hatert, F., Nickel, E.H. and Ferraris, G. (2009) The standardisation of mineral group hierarchies: Application to recent nomenclature proposals. European Journal of Mineralogy, 21, 1073–1080.CrossRefGoogle Scholar
Mills, S.J., Hager, S.L., Leverett, P., Williams, P.A. and Raudsepp, M. (2010 a) The crystal structure of H3O+-exchanged pharmacosiderite. Mineralogical Magazine, 74, 487–492.CrossRefGoogle Scholar
Mills, S.J., Kampf, A.R., Williams, P.A., Leverett, P., Poirier, G., Raudsepp, M. and Francis, C.A. (2010 b) Hydroniumpharmacosiderite, a new member of the pharmacosiderite supergroup from Cornwall: structure and description. Mineralogical Magazine, 74, 863–869.CrossRefGoogle Scholar
Mills, S.J., Raudsepp, M., Kampf, A.R., Hager, S.L., Leverett, P., Williams, P.A., Hibbs, D.E. and Birch, W.D. (2011) The crystal chemistry of natro-pharmacosiderite, bariopharmacosiderite-C and bariopharmacosiderite-Q. The Canadian Mineralogist (submitted).Google Scholar
Mutter, G., Eysel, W., Greis, O. and Schmetzer, K. (1984) Crystal chemistry of natural and ion-exchanged pharmacosiderites. Neues Jahrbuch für Mineralogie, Monatshefte, 183–192.Google Scholar
Peacor, D.R. and Dunn, P.J. (1985) Sodium-pharmaco-siderite – a new analog of pharmacosiderite from Australia and new occurrences of barium-pharma-cosoderite. Mineralogical Record, 16, 121–124.Google Scholar
Pouchou, J.L. and Pichoir, F. (1988) A simplified version of the ‘PAP’ model for matrix corrections in EPMA. Pp. 315–318 in: Microbeam Analysis (Newbury, D.E., editor). San Francisco Press, San Francisco, California, USA.Google Scholar
Schmetzer, K., Horn, W. and Bank, H. (1981) Alumopharmakosiderite, K[Al4(OH)4(AsO4)3].6.5H2O, ein neues Mineral. Neues Jahrbuch für Mineralogie, Monatshefte, 97–102.Google Scholar
Sejkora, J., Ondruš, P., Fikar, M., Veselovský, F., Mach, Z., Gabašová, A., Škoda, R. and Beran, P. (2006) Supergene minerals at the Huber stock and Schöd stock deposits, Krásno ore district, the Slavkovský les area, Czech Republic. Journal of the Czech Geological Society, 51, 57–101.Google Scholar
Sejkora, I., Škovíra, J., Čejka, I. and Plášil, I. (2009) Cu-rich members of the beudantite-segnitite series from the krupka ore district, the Krusne Hory Mountains, Czech Republic. Journal of GeoSciences, 54, 355–371.Google Scholar
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112–122.CrossRefGoogle Scholar
Sierra Lopez, J., Leal, G., Perriot, R., Laurent, Y., Protas, J. and Dusausoy, Y. (1968) La rodalquilarite, chlorotellurite de fer, une nouvelle espece minerale. Bulletin de Mineralogie 91, 28–33 (in French with English absract).Google Scholar
Yakovenchuk, V.N., Nikolaev, A.P., Selivanova, E.A., Pakhomovsky, Y.A., Korchak, J.A., Spiridonova, D.V., Zalkind, O.A. and Krivovichev, S.V. (2009) Ivanyukite-Na-T, ivanyukite-Na-C, ivanyukite-K, and ivanyukite-Cu: New microporous titanosilicates from the Khibiny massif (Kola peninsula, Russia) and crystal structure of ivanyukite-Na-T. American Mineralogist, 94, 1450–1458.CrossRefGoogle Scholar
Zemann, J. (1948) Formel und Struktur des pharmako-siderites. Tschermaks Mineralogische und Petrographische Mitteilungen, Third Series, 1, 1–13.CrossRefGoogle Scholar