Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-14T23:20:04.028Z Has data issue: false hasContentIssue false
  • English
  • Français

Ferrivauxite, a new phosphate mineral from Llallagua, Bolivia

Published online by Cambridge University Press:  02 January 2018

G. Raade ,
J. D. Grice  and
R. Rowe
G. Raade*
Affiliation:
Natural History Museum, University of Oslo, PO Box 1172 Blindern, NO-0318 Oslo, Norway
J. D. Grice
Affiliation:
Canadian Museum of Nature, PO Box 3443, Station ‘D’, Ottawa, Ontario, K1P 6P4, Canada
R. Rowe
Affiliation:
Canadian Museum of Nature, PO Box 3443, Station ‘D’, Ottawa, Ontario, K1P 6P4, Canada
*
*E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Ferrivauxite, ideally Fe3+ Al2(PO4)2(OH)3·5H2O, is an oxidized equivalent of vauxite, Fe2+ Al2(PO4)2(OH)2·6H2O, and forms oxidation pseudomorphs after that mineral. It occurs in association with sigloite and crandallite at the Llallagua tin deposit, Bolivia. It is triclinic, space group P1̄, with a = 9.198(2), b = 11.607(3), c = 6.112(2) Å, α = 98.237(9), β = 91.900(13), γ = 108.658(9)°, V = 609.7(5) Å3, Z = 2. Strongest reflections of the powder X-ray diffraction pattern are [dobs in Å(Iobs)(hkl)]: 10.834(100)(010), 8.682(24)(100), 8.242 (65)(110), 6.018(28)(001), 5.918(23)(1̄10), 5.491 (30)(1̄20), 4.338(26)(200), 2.898 (32)(300). The structure was refined to R1 = 0.0369 for 3244 observed reflections. Twinning occurs on {010}. Ferrivauxite is isotypic with vauxite but with positional disorder of the Fe1 site and some of the oxygen sites. Disorder is also indicated by the infrared spectrum. One of the water molecules in vauxite is deprotonated in conjunction with the oxidation process and becomes a hydroxyl group. Ferrivauxite is translucent to transparent, has a golden brown colour with a pale yellow-brown streak and vitreous lustre. It is brittle with an irregular fracture and shows no cleavage. The Mohs hardness is estimated to be ∼3½ by comparison with vauxite. D(calc.) is 2.39 g cm–3 for the empirical formula Fe3+0.94Mn0.01Al1.98P2.05O8(OH)3 · 5H2O, obtained by electron-microprobe analysis in wavelength dispersive spectroscopy mode. The mineral is optically biaxial negative with α = 1.589(1), β = 1.593(1), γ = 1.596(1); the refractive indices are higher than those of vauxite.

Keywords

FerrivauxiteNew MineralCrystal StructurePowder X-ray Diffraction DataHydrogen BondingInfrared SpectroscopyLlallagua Tin DepositBolivia
Type
Research Article
Information
Mineralogical Magazine , Volume 80 , Issue 2 , April 2016 , pp. 311 - 324
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2016

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, pp. 625 pp.Google Scholar
Baur, W.H. (1969) The crystal structure of paravauxite, Fe2+A12(PO4)2(OH)2(OH2)6-2H2O. Neues Jahrbuch für Mineralogie, Monatshefte, 430—433.Google Scholar
Baur, W.H. and Rama Rao, B. (1968) The crystal structure and the chemical composition of vauxite. American Mineralogist, 53, 1025–1028. Google Scholar
Brese, N.E. and O'Keeffe, M. (1991) Bond-valence parameters for solids. Acta Crystallographica, B47, 192–197. CrossRefGoogle Scholar
Brown, I.D. and Altermatt, D. (1985) Bond-valence parameters obtained from a systematic analysis of the inorganic crystal structure database. Acta Crystallographica, B, 244–247. CrossRefGoogle Scholar
Chukanov, N.V. (2014) Infrared Spectra of Mineral Species: Extended Library.Springer-Verlag GmbH, Dordrecht — Heidelberg — New York — London. 1716 pp.CrossRefGoogle Scholar
Gatta, G.D., Vignola, P. and Meven, M. (2014) On the complex H-bonding network in paravauxite, Fe2+A12(PO4)2(OH)2-8H2O: A single-crystal neutron diffraction study. Mineralogical Magazine, 78, 841–850. CrossRefGoogle Scholar
Gordon, S.G. (1923) Vauxite and paravauxite, two new minerals from Llallagua, Bolivia. Proceedings of the Academy of Natural Sciences of Philadelphia, 75, 261–267. Google Scholar
Gordon, S.G. (1944) The mineralogy of the tin mines of Cerro de Llallagua, Bolivia. Proceedings of the Academy of Natural Sciences of Philadelphia, 96, 279–359. Google Scholar
Hawthorne, F.C. (1988) Sigloite: the oxidation mechan¬ism in [M-+(PO4)2(OH)2(H2O)2]2∼ structures. Mineralogy and Petrology, 38, 201—211 CrossRefGoogle Scholar
Hurlbut, C.S.Jr and Honea, R. (1962) Sigloite, a new mineral from Llallagua, Bolivia. American Mineralogist, 47, 1—8.Google Scholar
Hyrsl, J. and Petrov, A. (2006) Famous mineral localities: Llallagua, Bolivia. Mineralogical Record, 37,117–162 Google Scholar
Kraus, W and Nolze, G. (1996) Powdercell - a program for the representation and manipulation of crystal structures and calculation of the resulting X-ray powder patterns. Journal of Applied Crystallography, 29, 301–303. CrossRefGoogle Scholar
Laugier, J. and Bochu, B. (2003) LMGP Suite of Programs for the Interpretation of X-ray Experiments. ENSP/Laboratoire des Matériaux et du Génie Physique, BP 46. 38042 Saint Martin d'Heres, France.Google Scholar
Libowitzky, E. (1999) Correlation of O-H stretching frequencies and O—H-0 hydrogen bond lengths in minerals. Monatshefte für Chemie, 130,1047–1059 CrossRefGoogle Scholar
Mandarino, J.A. (1981) The Gladstone-Dale relationship: Part IV. The compatibility concept and its application. The Canadian Mineralogist, 19, 441—450 Google Scholar
Moore, P.B. and Araki, T (1974) Montgomeryite, Ca4Mg(H2O)12[Al4(OH)4(PO4)6]: Its crystal structure and relation to vauxite, • 4H2O. Fe2+ (H2O)4 [Al4 ðOHÞ4 ðH2OÞ4 ðPO4Þ4 American Mineralogist, 59, 843–850. Google Scholar
Moore, P.B., Araki, T., Kampf, A.R. and Steele, I.M. (1976) Olmsteadite, K2Fe22þ[Fe22þ(Nb,Ta)2 5O4ðH2OÞ4ðPO4Þ4], a new species, its crystal structure and relation to vauxite and montgomeryite. American Mineralogist, 61, 5–11. Google Scholar
Rowe, R. (2009) New statistical calibration approach for Bruker AXS D8 Discover microdiffractometer with Hi-Star detector using GADDS software. Powder Diffraction, 24, 263–271. CrossRefGoogle Scholar
Sheldrick, G.M. (1990) SHELXTL, a crystallographic computing package, revision 4.1. Siemens Analytical Instruments, Inc., Madison, Wisconsin, USA.Google Scholar
Sheldrick, G.M. (1998) SADABS User Guide. University of Göttingen. Göttingen, German.Google Scholar