Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-27T07:16:51.442Z Has data issue: false hasContentIssue false
  • English
  • Français

Juansilvaite, Na5Al3[AsO3(OH)]4[AsO2(OH)2]2(SO4)2·4H2O, a new arsenate-sulfate from the Torrecillas mine, Iquique Province, Chile

Published online by Cambridge University Press:  02 January 2018

Anthony R. Kampf ,
Barbara P. Nash ,
Maurizio Dini  and
Arturo A. Molina Donoso
Anthony R. Kampf*
Affiliation:
Mineral Sciences Department, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA
Barbara P. Nash
Affiliation:
Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112, USA
Maurizio Dini
Affiliation:
Pasaje San Agustin 4045, La Serena, Chile
Arturo A. Molina Donoso
Affiliation:
Los Algarrobos 2986, Iquique, Chile
*
*E-mail: akampf@nhm.org
Get access Rights & Permissions [Opens in a new window]

Abstract

The new mineral juansilvaite (IMA2015-080), Na5Al3[AsO3(OH)]4[AsO2(OH)2]2(SO4)2·4H2O, was foOptically, juansilvaiteund at the Torrecillas mine, Iquique Province, Chile, where it occurs as asecondary alteration phase in association with anhydrite, canutite, halite, sulfur and a mahnertite-like phase. Juansilvaite occurs as bright pink blades up to ∼0.5 mm long grouped in tightly intergrown radial aggregates and also as opaque dull pale pink rounded aggregates. Blades areflattened on {001}, elongated on [100] and exhibit the forms {001}, {111} and {201}. Crystals are transparent, with vitreous lustre and white streak. The Mohs hardness is ∼2½, tenacity is brittle and fracture is irregular. Cleavage is very good on {001}. The measured density is3.01(2) g cm–3 and the calculated density is 3.005 g cm–3. Optically, juansilvaite is biaxial (+) with α= 1.575(1), β = 1.597(1), γ= 1.623(1) and 2V = 86(1)° (measured in white light). Dispersion is r < v, slight, andthe orientation is X = b; Z ^ c = 27° in the obtuse angle β. The pleochroism is X > Y ≈ Z in shades of pale pink. The mineral is slowly soluble in dilute HCl at room temperature. The empirical formula, determined from electron-microprobeanalyses, is Na4.95Al2.28Fe0.503+Mn0.213+Cu0.04As5.92S1.83O36H17.37. Juansilvaite is monoclinic, C2/c, a = 18.1775(13), b = 8.6285(5), c= 18.5138(13) Å, β = 90.389(6)°, V = 2903.7(3) Å3 and Z = 4. The eight strongest powder X-ray diffraction lines are [dobs Å(I)(hkl)]: 9.25(100)(002), 7.20(34)(111), 4.545(34)(400), 3.988(39)(114), 3.363(42)(314), 3.145(66)(512,420), 2.960(68)(422,422) and 2,804(33)(131,423). The structure of juansilvaite (R1 = 3.82% for 2040 Fo > 4σF reflections) contains layers made up of alternating corner-linked Al–O octahedra and acid-arsenate tetrahedra. Sodium cations occur both peripheral to the layers and within cavities in the layers. An SO4 tetrahedron and an H2O group also are in the interlayer region.

Keywords

juansilvaitenew mineralarsenate-sulfatecrystal structureTorrecillas mineChile
Type
Research Article
Information
Mineralogical Magazine , Volume 81 , Issue 3 , June 2017 , pp. 619 - 628
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2017

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

Boudjada, A. and Guitel, J.C. (1981) Structure cristalline d'un orthoarsénate acide de fer(III) pentahydraté: Fe(H2AsO4)3-5H2O. Acta Crystallographica, B37, 1402–1405.CrossRefGoogle Scholar
Brown, I.D. and Altermatt, D. (1985) Bond-valence parameters from a systematic analysis of the inorganic crystal structure database. Acta Crystallographica, B41, 244–247.CrossRefGoogle Scholar
Burla, M. C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G.L., Giacovazzo, C., Mallamo, M., Mazzone, A., Polidori, G. and Spagna, R. (2012) SIR2011: a new package for crystal structure determination and refinement. Journal of Applied Crystallography, 45, 357–361.CrossRefGoogle Scholar
Cameron, E.M., Leybourne, M.I. and Palacios, C. (2007) Atacamite in the oxide zone of copper deposits in northern Chile: involvement of deep formation waters. Mineralium Deposita, 42, 205–218.CrossRefGoogle Scholar
Demartin, F., Castellano, C., Gramaccioli, C.M. and Campostrini, I. (2010) Aluminum-for-iron substitution, hydrogen bonding and a novel structure type in coquimbite-like minerals. The Canadian Mineralogist, 48, 323–333.CrossRefGoogle Scholar
Dick, S., Goßner, U., Weiß, A., Robl, C., Großmann, G., Ohms, G. and Zeiske, T. (1998) Taranakite-the mineral with the longest crystallographic axis. lnorganica Chimica Acta, 269, 47–57.CrossRefGoogle Scholar
Gutiérrez, H. (1975) Informe sobre una rápida visita a la mina de arsénico nativo, Torrecillas. Instituto de Investigaciones Geológicas, Iquique, Chile.Google Scholar
Higashi, T. (2001) ABSCOR. Rigaku Corporation, Tokyo.Google Scholar
Kampf, A.R., Sciberras, M.J., Williams, P.A., Dini, M. and Molina Donoso, A.A. (2013a) Leverettite from the Torrecillas mine, Iquique Provence, Chile: the Co-analogue of herbertsmithite. Mineralogical Magazine, 77, 3047–3054.CrossRefGoogle Scholar
Kampf, A.R., Nash, B.P., Dini, M. and Molina Donoso, A. A. (2013b) Magnesiokoritnigite, Mg(AsO3OH)-H2O, from the Torrecillas mine, Iquique Province, Chile: the Mg-analogue of koritnigite. Mineralogical Magazine, 77, 3081–3092.CrossRefGoogle Scholar
Kampf, A.R., Mills, S.J., Nash, B.P., Housley, R.M., Rossman, G.R. and Dini, M. (2013c) Camaronesite, [Fe3+(H2O)2(PO3OH)]2(SO4)-1-2H2O, a new phosphate-sulfate from the Camarones Valley, Chile, structurally related to taranakite. Mineralogical Magazine, 77, 453–465.CrossRefGoogle Scholar
Kampf, A.R., Nash, B.P., Dini, M. and Molina Donoso, A. A. (2014a) Torrecillasite, NaAs,Sb)3+4O6Cl, a new mineral from the Torrecillas mine, Iquique Province, Chile: description and crystal structure. Mineralogical Magazine, 78, 747–755.CrossRefGoogle Scholar
Kampf, A.R., Mills, S.J., Hatert, F., Nash, B.P., Dini, M. and Molina Donoso, A.A. (2014b) Canutite, NaMn3 [AsO4]2[AsO2(OH)2], a new protonated alluaudite-group mineral from the Torrecillas mine, Iquique Province, Chile. Mineralogical Magazine, 78, 787–795.CrossRefGoogle Scholar
Kampf, A.R., Nash, B., Dini, M. and Molina Donoso, A. A. (2015) Juansilvaite, IMA 2015-080. CNMNC Newsletter No. 28, December 2015, page 1863. Mineralogical Magazine, 79, 1859–1864.Google Scholar
Kampf, A.R., Nash, B.P., Dini, M. and Molina Donoso, A.A. (2016a) Chongite, Ca3Mg2(AsO4)2(AsO3OH)2-4H2O, a new arsenate member of the hureaulite group from the Torrecillas mine, Iquique Province, Chile. Mineralogical Magazine, 80, 1255–1263.CrossRefGoogle Scholar
Kampf, A.R., Nash, B.P., Dini, M. and Molina Donoso, A.A. (2016b) Gajardoite, KCa,,5As4+O6Cl2-5H2O, a new mineral related to lucabindiite and torrecillasite from the Torrecillas mine, Iquique Province, Chile. Mineralogical Magazine, 80, 1265–1272.CrossRefGoogle Scholar
Mandarino, J.A. (2007) The Gladstone-Dale compatibility of minerals and its use in selecting mineral species for further study. The Canadian Mineralogist, 45, 1307–1324.CrossRefGoogle Scholar
Majzlan, J., Ðorđevic, T., Kolitsch, U. and Schefer, J. (2010) Hydrogen bonding in coquimbite, nominally Fe2(SO4)3-9H2O, and the relationship between coquimbite and paracoquimbite. Mineralogy and Petrology, 100, 241–248.CrossRefGoogle Scholar
Pouchou, J.-L. and Pichoir, F. (1991) Quantitative analysis of homogeneous or stratified microvo-lumes applying the model “PAP.” Pp. 3l-75 in: Electron Probe Quantitation (K.F.J. Heinrich and D.E. Newbury, editors). Plenum Press, New York.Google Scholar
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112–122.CrossRefGoogle Scholar
Wood, R.M. and Palenik, G.J. (1999) Bond valence sums in coordination chemistry. Sodium-oxygen complexes. Inorganic Chemistry, 38, 3926–3930.CrossRefGoogle Scholar