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Fluorcalcioroméite, (Ca,Na)2Sb25+(O,OH)6F, a new roméite-group mineral from Starlera mine, Ferrera, Grischun, Switzerland: description and crystal structure

Published online by Cambridge University Press:  05 July 2018

D. Atencio ,
M. E. Ciriotti  and
M. B. Andrade
D. Atencio*
Affiliation:
Departamento de Mineralogia e Geotectônica, Instituto de Geociências, Universidade de São Paulo, Rua do Lago, 562, 05508-080 São Paulo, SP, Brazil
M. E. Ciriotti
Affiliation:
Associazione Micromineralogica Italiana, via San Pietro 55, I-10073 Devesi-Ciriè, Italy
M. B. Andrade
Affiliation:
Department of Geosciences, University of Arizona, 1040 East 4th Street, Tucson, Arizona 85721, USA
*
* E-mail: [email protected]
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Abstract

Fluorcalcioroméite, (Ca,Na)2Sb25+(O,OH)6F, is a new roméite-group, pyrochlore-supergroup mineral (IMA 2012-093), from Starlera mine, Ferrera, Hinterrhein district, Grischun, Switzerland. The intimately associated minerals are: braunite, hematite, calcite, quartz and, rarely, wallkilldellite-(Mn). It occurs as euhedral octahedra, untwinned, from 0.1 to 1 mm in size. The crystals are yellow to orange and translucent; the streak is white, and the lustre is vitreous to resinous. It is non-fluorescent under ultraviolet light. Mohs' hardness is ∼5½, tenacity is brittle. Cleavage is not observed; fracture is conchoidal. The calculated density is 5.113 g/cm3. The mineral is isotropic, ncalc. = 1.826. The Raman spectrum is dominated by bands of Sb–O octahedral bond stretching and O–Sb–O bending modes. The chemical composition (n = 13) is (by wavelength-dispersive spectroscopy (WDS), H2O calculated by difference, wt.%): Na2O 4.11, CaO 15.41, MnO 0.54, CuO 0.01, ZnO 0.01, PbO 0.02, Al2O3 0.10, FeO 0.50, Y2O3 0.07, SiO2 0.04, TiO2 0.01, UO2 0.01, Sb2O5 76.18, WO3 0.78, F 2.79, H2O 0.59, O = F–1.17, total 100.00. The empirical formula, based on 2 cations at the B site, is (Ca1.16Na0.56☐0.22Fe0.032+ Mn0.032+)Σ2.00(Sb5+1.98Al0.01W0.01)Σ2.00O6[F0.62(OH)0.28O0.06☐0.04]Σ1.00. The strongest eight X-ray powder-diffraction lines [d in Å (I)(hkl)] are: 5.934(81)(111), 3.102(20)(311), 2.969(100)(222), 2.572(6)(400), 1.979(7)(333), 1.818(8)(440), 1.551(15)(622), and 1.484(5)(444). The crystal structure refinement (R1 = 0.0106) gave the following data: cubic, Fdm, a = 10.2987(8) Å, V = 1092.31(15) Å3, Z = 8. Unit-cell parameters refined from the powder data are: a = 10.284(2), V = 1087.7(7) Å3, Z = 8.

Keywords

fluorcalcioroméitenew mineralStarlera mineFerreraGrischunSwitzerlandpyrochlore supergrouproméite groupcrystal structure
Type
Research Article
Information
Mineralogical Magazine , Volume 77 , Issue 4 , June 2013 , pp. 467 - 473
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2013

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References

Atencio, D., Andrade, M.B., Christy, A.G., Gieré, R. and Kartashov, P.M. (2010) The pyrochlore supergroup of minerals nomenclature. The Canadian Mineralogist, 48, 673–698.CrossRefGoogle Scholar
Bahfenne, S. and Frost, R.L. (2010) Raman spectroscopic study of the antimonate mineral roméite. Spectrochimica Acta, A75, 637–639.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, B41, 244–247.CrossRefGoogle Scholar
Brugger, J. and Gieré, R. (1999) As, Sb B. and Ce enrichment in minerals from a metamorphosed Fe- Mn deposit, Val Ferrera, Eastern Swiss Alps. The Canadian Mineralogist, 37, 37–52.Google Scholar
Brugger, J. and Gieré, R. (2000) Origin and distribution of some trace elements in metamorphosed Fe-Mn deposits, Val Ferrera, Eastern Swiss Alps. The Canadian Mineralogist, 38, 1075–1101.CrossRefGoogle Scholar
Brugger, J., Gieré, R., Graeser, S. and Meisser, N. (1997) The crystal chemistry of romé ite. Contributions to Mineralogy and Petrology, 127, 136–146.CrossRefGoogle Scholar
Brugger, J., Krivovichev, S.V., Kolitsch, U., Meisser, N., Andrut, M., Ansermet, S. and Burns, P.C. (2002) Description and crystal structure of manganlotharmeyerite, Ca(Mn3+,□,Mg)2{AsO4,[AsO2(OH)2]}2 (OH,H2O)2, from the Starlera Mn deposit, Swiss Alps, and a redefinition of lotharmeyerite. The Canadian Mineralogist, 40, 1597–1608.CrossRefGoogle Scholar
Downs, R.T., Bartelmehs, K.L., Gibbs, G.V. and Boisen, M.B. (1993) Interactive software for calculating and displaying X-ray or neutron powder diffractometer patterns of crystalline materials. American Mineralogist, 78, 1104–1107.Google Scholar
Frost, R.L. and Bahfenne, S. (2010) Raman spectroscopy study of the antimonite mineral lewisite (Ca,Fe,Na)2(Sb,Ti)2O6(O,OH)7 . Radiation Effects and Defects in Solids, 165, 46–53.CrossRefGoogle Scholar
Hussak, E. and Prior, G.T. (1895) Lewisite and zirkelite, two new Brazilian minerals. Mineralogical Magazine, 11, 80–88.CrossRefGoogle Scholar
Lumpkin, G.R. and Ewing, R.C. (1995) Geochemical alteration of pyrochlore group minerals: pyrochlore subgroup. American Mineralogist, 80, 732–743.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
Miura, H. (2003) CellCalc: A unit-cell parameter refinement program on Windows computer. Journal of the Crystallographic Society of Japan, 45, 145–147. (in Japanese).CrossRefGoogle Scholar
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112–122.CrossRefGoogle Scholar
Subramanian, M.A., Aravamudan, G. and Rao, V.S. (1983) Oxide pyrochlores – a review. Progress in Solid State Chemistry, 15, 55–143.CrossRefGoogle Scholar
Uher, P., Černý, P., Chapman, R., Határ, J. and Miko, O. (1998) Evolution of Nb,Ta-oxide minerals in the Prašivá granitic pegmatites, Slovakia. II. External hydrothermal Pb,Sb overprint. The Canadian Mineralogist, 36, 535–545.Google Scholar