Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-13T12:25:20.005Z Has data issue: false hasContentIssue false
  • English
  • Français

Torrecillasite, Na(As,Sb)43+O6Cl, a new mineral from the Torrecillas mine, Iquique Province, Chile: description and crystal structure

Published online by Cambridge University Press:  05 July 2018

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

Abstract

The new mineral torrecillasite (IMA2013-112), Na(As,Sb)43+O6Cl, was found at the Torrecillas mine, Iquique Province, Chile, where it occurs as a secondary alteration phase in association with anhydrite, cinnabar, gypsum, halite, lavendulan, magnesiokoritnigite, marcasite, quartz, pyrite, scorodite, wendwilsonite and other potentially new As-bearing minerals. Torrecillasite occurs as thin colourless prisms up to 0.4 mm long in jack-straw aggregates, as very thin fibres in puff balls and as massive intergrowths of needles. Prisms are elongated on [100] with diamond-shaped cross-section and irregular terminations. Crystals are transparent, with adamantine lustre and white streak. The Mohs hardness is 2½, tenacity is brittle and fracture is irregular. Cleavage on (001) is likely. The calculated density is 4.056 g cm−3. Optically, torrecillasite is biaxial (−) with α = 1.800(5), β = 1.96(1), γ = 2.03(calc.) (measured in white light). The measured 2V is 62.1(5)°, no dispersion or pleochroism were observed, the optical orientation is X = c, Y = b, Z = a. The mineral is very slowly soluble in H2O, slowly soluble in dilute HCl and rapidly soluble in concentrated HCl. The empirical formula, determined from electron-microprobe analyses, is (Na1.03Mg0.02)∑1.05(As3.39Sb0.62)∑4.01O6.07Cl0.93. Torrecillasite is orthorhombic, Pmcn, a = 5.2580(9), b = 8.0620(13), c = 18.654(3) Å, V = 790.7(2) Å3 and Z = 4. The eight strongest X-ray powder diffraction lines are [dobs Å(I)(hkl)]: 4.298(33)(111), 4.031(78)(014,020), 3.035(100)(024,122), 2.853(39)(115,123), 2.642(84)(124,200), 2.426(34)(125), 1.8963(32)(225) and 1.8026(29)(0·1·10,233). The structure, refined to R1 = 4.06% for 814 Fo >4σF reflections, contains a neutral, wavy As2O3 layer parallel to (001) consisting of As3+O3 pyramids that share O atoms to form six-membered rings. Successive layers are flipped relative to one another and successive interlayer regions contain alternately either Na or Cl atoms. Torrecillasite is isostructural with synthetic orthorhombic NaAs4O6Br.

Keywords

torrecillasitenew mineralarsenitecrystal structureTorrecillas mineChile
Type
Research Article
Information
Mineralogical Magazine , Volume 78 , Issue 3 , June 2014 , pp. 747 - 755
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2014

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

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 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., De Caro, L., Giacovazzo, C., Polidori, G. and Spagna, R. (2005) SIR2004: an improved tool for crystal structure determination and refinement. Journal of Applied Crystallography, 38, 381–388.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
Garavelli, A., Mitolo, D., Pinto, D. and Vurro, F. (2013) Lucabindiite, (K,NH4)As4O6(Cl,Br), a new fumarole mineral from the “La Fossa” crater at Vulcano, Aeolian Islands, Italy. American Mineralogist, 98, 470–477.CrossRefGoogle Scholar
Gunter, M.E., Bandli, B.R., Bloss, F.D., Evans, S.H., Su, S.C. and Weaver, R. (2004) Results from a McCrone spindle stage short course, a new version of EXCALIBR, and how to build a spindle stage. The Microscope, 52, 23–39.Google Scholar
Gutiérrez, H. (1975) Informe sobre una rápida visita a la mina de arsénico nativo, Torrecillas. Instituto de Investigaciones Geoló gicas, Iquique, Chile.Google Scholar
Higashi, T. (2001) ABSCOR. Rigaku Corporation, Tokyo.Google Scholar
Kampf, A.R., Nash, B.P., Dini, M. and Molina Donoso, A.A. (2013a) 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., Sciberras, M.J., Williams, P.A., Dini, M. and Molina Donoso, A.A. (2013b) Leverettite from the Torrecillas mine, Iquique Provence, Chile: the Co-analogue of herbertsmithite Mineralogical Magazine, 77, 3047–3054.CrossRefGoogle Scholar
Kampf, A.R., Mills, S.J., Hatert, F., Nash, B.P., Dini, M. and Molina Donoso, A.A. (2014) Canutite, NaMn3[AsO4]2[AsO2(OH)2], a new protonated alluaudite-group mineral from the Torrecillas mine, Iquique Province, Chile. Mineralogical Magazine, 78, (in press).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
Mills, S.J., Christy, A.G., Chen, E.C.-C. and Raudsepp, M. (2009) Revised values of the bond valence parameters for [6]Sb(V)–O and [3–11]Sb(III)–O. Zeitschrift für Kristallographie, 224, 423–431.CrossRefGoogle Scholar
Mortimer, C., Saric, N. and Cáceres, R. (1971) Apuntes sobre algunas minas de la región costera de la provincia de Tarapacá. Instituto de Investigaciones Geoló gicas, Santiago de Chile, Chile.Google Scholar
Pimentel, F. (1978) Proyecto Arsenico Torrecillas. Instituto de Investigaciones Geológicas, Iquique, Chile.Google Scholar
Pertlik, F. (1987) The crystal structure of NaAs4O6Br. Journal of Solid State Chemistry, 70, 225–228.CrossRefGoogle Scholar
Pertlik, F. (1988) The compounds KAs4O6X (X = Cl, Br, I) and NH4As4O6X (X = Br, I): hydrothermal syntheses and structure determinations. Monatshefte für Chemie, 119, 451–456.CrossRefGoogle Scholar
Pouchou, J.-L. and Pichoir, F. (1991) Quantitative analysis of homogeneous or stratified microvolumes 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
Wright, S.E., Foley, J.A. and Hughes, J.M. (2001) Optimization of site occupancies in minerals using quadratic programming. American Mineralogist, 85, 524–531.CrossRefGoogle Scholar