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Experimental evidence for partial Fe2+ disorder at the Y and Z sites of tourmaline: a combined EMP, SREF, MS, IR and OAS study of schorl

Published online by Cambridge University Press:  02 January 2018

Ferdinando Bosi ,
Giovanni B. Andreozzi ,
Ulf Hålenius  and
Henrik Skogby
Ferdinando Bosi*
Affiliation:
Dipartimento di Scienze della Terra, Sapienza Università di Roma, Piazzale Aldo Moro, 5, I-00185 Rome, Italy Department of Geosciences, Swedish Museum of Natural History, Box 50007, SE-10405 Stockholm, Sweden
Giovanni B. Andreozzi
Affiliation:
Dipartimento di Scienze della Terra, Sapienza Università di Roma, Piazzale Aldo Moro, 5, I-00185 Rome, Italy
Ulf Hålenius
Affiliation:
Department of Geosciences, Swedish Museum of Natural History, Box 50007, SE-10405 Stockholm, Sweden
Henrik Skogby
Affiliation:
Department of Geosciences, Swedish Museum of Natural History, Box 50007, SE-10405 Stockholm, Sweden
*
*E-mail: ferdinando.bosi@uniroma1.it
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Abstract

An experimental study of an Al-rich schorl sample from Cruzeiro mine (Minas Gerais, Brazil) was carried out using electron microprobe analysis, structural refinement and Mössbauer, infrared and optical absorption spectroscopy in order to explore the disordering of Fe2+ over the Y and Z sites of the tourmaline structure.

A structural formula was obtained by merging chemical and structural data. The cation distribution at the two non-equivalent octahedrally coordinated sites (Y and Z) was obtained by two different optimization procedures which, minimizing the residuals between observed and calculated data, converged to the formula: X(Na0.65〈0.32Ca0.02K0.01)Σ1.00Y(Fe1.652+Al1.15Fe0.063+Mn0.052+Zn0.05Ti0.044+)Σ3.00Z(Al5.52Fe0.302+Mg0.18)Σ6.00[T(Si5.87Al0.13)Σ6.00O18](BBO3)3V(OH)3W[(OH)0.34F0.28O0.38]Σ1.00.

This result shows a partial disordering of Fe2+ over the Y and Z sites which explains adequately the mean atomic number observed for the Z site (13.5±0.1). Such a disordering is also in line with the shoulder recorded in the Mössbauer spectrum (fitted by a doublet with isomer shift of 1.00 mm/s and quadrupole splitting of 1.38 mm/s) as well as with the asymmetric bands recorded in the optical absorption spectrum at ∼9000 and 14,500 cm–1 (modelled by four Gaussian bands, centred at 7677 and 9418 cm–1, and 13,154 and 14,994 cm–1, respectively).

The high degree of consistency in the results obtained using the different methods suggests that the controversy over Fe2+ order can be ascribed to the failure to detect small amounts of Fe2+ at Z (typically <<10% atoms/site) rather than a steric effect of Fe2+ on the tourmaline structure.

Keywords

tourmalineschorlcrystal-structure refinementelectron microprobeMössbauer spectroscopyoptical absorption spectroscopyinfrared spectroscopy
Type
Research Article
Information
Mineralogical Magazine , Volume 79 , Issue 3 , June 2015 , pp. 515 - 528
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2015

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References

Andreozzi, G.B., Bosi, F. and Longo, M. (2008) Linking Mössbauer and structural parameters in elbaiteschorl-dravite tourmalines. American Mineralogist, 93, 658–666.CrossRefGoogle Scholar
Bosi, F. (2008) Disordering of Fe2+ over octahedrally coordinated sites of tourmaline. American Mineralogist, 93, 1647–1653.CrossRefGoogle Scholar
Bosi, F. (2010) Octahedrally coordinated vacancies in tourmaline: a theoretical approach. Mineralogical Magazine, 74, 1037–1044.CrossRefGoogle Scholar
Bosi, F. (2011) Stereochemical constraints in tourmaline: from a short-range to a long-range structure. The Canadian Mineralogist, 49, 17–27.CrossRefGoogle Scholar
Bosi, F. (2013) Bond-valence constraints around the O1 site of tourmaline. Mineralogical Magazine, 77, 343–351.CrossRefGoogle Scholar
Bosi, F. and Skogby, H. (2013) Oxy-dravite, Na(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup. American Mineralogist, 98, 1442–1448.CrossRefGoogle Scholar
Bosi, F. and Lucchesi, S. (2004) Crystal chemistry of the schorl-dravite series. European Journal of Mineralogy, 16, 335–344.CrossRefGoogle Scholar
Bosi, F. and Lucchesi, S. (2007) Crystal chemical relationships in the tourmaline group: structural constraints on chemical variability. American Mineralogist, 92, 1054–1063.CrossRefGoogle Scholar
Bosi, F. and Andreozzi, G.B. (2013) A critical comment on Ertl et al. (2012) “Limitations of Fe2+ and Mn2+ site occupancy in tourmaline: Evidence from Fe2+-and Mn2+-rich tourmaline”. American Mineralogist, 98, 2183–2192.CrossRefGoogle Scholar
Bosi, F., Andreozzi, G.B., Federico, M., Graziani, G. and Lucchesi, S. (2005) Crystal chemistry of the elbaite-schorl series. American Mineralogist, 90, 1784–1792.CrossRefGoogle Scholar
Bosi, F., Balić-Žunić, T. and Surour, A.A. (2010) Crystal structure analysis of four tourmalines from the Cleopatra’s Mines (Egypt) and Jabal Zalm (Saudi Arabia), and the role of Al in the tourmaline group. American Mineralogist, 95, 510–518.CrossRefGoogle Scholar
Bosi, F., Skogby, H., Agrosì, G. and Scandale, E. (2012) Tsilaisite, NaMn3Al6(Si6O18)(BO3)3(OH)3OH, a new mineral species of the tourmaline supergroup from Grotta d’Oggi, San Pietro in Campo, island of Elba, Italy. American Mineralogist, 97, 989–994.CrossRefGoogle Scholar
Bosi, F., Andreozzi, G.B., Agrosì, G. and Scandale, E. (2014) Fluor-tsilaisite, NaMn3Al6(Si6O18) (BO3)3(OH)3F, a new tourmaline from San Piero in Campo (Elba, Italy) and new data on tsilaisitic tourmaline from the holotype specimen locality. Mineralogical Magazine, 79, 89–101.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
Burns, R.G. (1972) Mixed valencies and site occupancies of iron in silicate minerals from Mössbauer spectroscopy. Canadian Journal of Spectroscopy, 17, 51–59.Google Scholar
Dutrow, B.L. and Henry, D.J. (2011) Tourmaline: A geologic DVD. Elements, 7, 301–306.CrossRefGoogle Scholar
Dyar, M.D., Taylor, M.E., Lutz, T.M., Francis, C.A., Guidotti, C.V. and Wise, M. (1998) Inclusive chemical characterization of tourmaline: Mössbauer study of Fe valence and site occupancy. American Mineralogist, 83, 848–864.CrossRefGoogle Scholar
Ertl, A., Kolitsch, U., Dyar, M.D., Hughes, J.M., Rossman, G.R., Pieczka, A., Henry, D.J., Pezzotta, F., Prowatke, S., Lengauer, C.L., Körner, W., Brandstatter, F., Francis, C.A., Prem, M. and Tillmans, E. (2012) Limitations of Fe2+ and Mn2+ site occupancy in tourmaline: evidence from Fe2+-and Mn2+-rich tourmaline. American Mineralogist, 97, 1402–1416.CrossRefGoogle Scholar
Federico, M., Andreozzi, G.B., Lucchesi, S., Graziani, G. and César-Mendes, J. (1998) Crystal chemistry of tourmalines. I. Chemistry, compositional variations and coupled substitutions in the pegmatite dikes of the Cruzeiro mine, Minas Gerais, Brazil. The Canadian Mineralogist, 36, 415–431.Google Scholar
Filip, J., Bosi, F., Novák, M., Skogby, H., Tuček, J., Čuda, J. and Wildner, M. (2012) Redox processes of iron in the tourmaline structure: example of the hightemperature treatment of Fe3+-rich schorl. Geochimica et Cosmochimica Acta, 86, 239–256.CrossRefGoogle Scholar
Foit, F.F. Jr. (1989) Crystal chemistry of alkali-deficient schorl and tourmaline structural relationships. American Mineralogist, 74, 422–431.Google Scholar
Fuchs, Y., Lagache, M. and Linares, J. (1998) Fetourmaline synthesis under different T and fO2 conditions. American Mineralogist, 83, 525–534.CrossRefGoogle Scholar
Gonzalez-Carren˜o, T., Fernandez, M. and Sanz, J. (1988) Infrared and electron micropobe analysis in tourmalines. Physics and Chemistry of Minerals, 15, 452–460.CrossRefGoogle Scholar
Grice, J.D. and Ercit, T.S. (1993) Ordering of Fe and Mg in the tourmaline crystal structure: the correct formula. Neues Jahrbuch für Mineralogie, Abhandlungen, 165, 245–266.Google Scholar
Hawkins, K.D., MacKinnon, I. and Schneeberger, H. (1995) Influence of chemistry on the pyroelectric effect in tourmaline. American Mineralogist, 80, 491–501.CrossRefGoogle Scholar
Hawthorne, F.C. (1996) Structural mechanisms for lightelement variations in tourmaline. The Canadian Mineralogist, 34, 123–132.Google Scholar
Hawthorne, F.C. (2002) Bond-valence constraints on the chemical composition of tourmaline. The Canadian Mineralogist, 40, 789–797.CrossRefGoogle Scholar
Henry, D.J. and Dutrow, B.L. (2011) The incorporation of fluorine in tourmaline: Internal crystallographic controls or external environmental influences? The Canadian Mineralogist, 49, 41–56.CrossRefGoogle Scholar
Henry, D.J., Novák, M., Hawthorne, F.C., Ertl, A., Dutrow, B., Uher, P. and Pezzotta, F. (2011) Nomenclature of the tourmaline supergroup minerals. American Mineralogist, 96, 895–913.CrossRefGoogle Scholar
Henry, D.J., Novák, M., Hawthorne, F.C., Ertl, A., Dutrow, B., Uher, P. and Pezzotta, F. (2013) Erratum. American Mineralogist, 98, 524. Lagarec, K. and Rancourt, D.G. (1998) RECOIL. Mössbauer spectral analysis software for Windows, version 1.0. Department of Physics, University of Ottawa, Canada. MacDonald, D.J. and Hawthorne, F.C. (1995) The crystal chemistry of Si = Al substitution in tourmaline. The Canadian Mineralogist, 33, 849–858.Google Scholar
Mattson, S.M. and Rossman, G.R. (1984) Ferric iron in tourmaline. Physics and Chemistry of Minerals, 11, 225–234.CrossRefGoogle Scholar
Mattson, S.M. and Rossman, G.R. (1987) Fe2+-Fe3+ interactions in tourmaline. Physics and Chemistry of Minerals, 14, 163–171.CrossRefGoogle Scholar
Pieczka, A. and Kraczka, J. (2004) Oxidized tourmalines-a combined chemical, XRD and Mössbauer study. European Journal of Mineralogy, 16, 309–321.CrossRefGoogle Scholar
Pouchou, J.L. and Pichoir, F. (1991) Quantitative analysis of homogeneous or stratified microvolumes applying the model “PAP”. Pp. 31–75. in: Electron Probe Quantitation (K.F.J. Heinrich and D.E. Newbury, editors). Plenum Press, New York.Google Scholar
Rozhdestvenskaya, I.V., Setkovab, T.V., Vereshchagina, O.S., Shtukenberga, A.G. and Shapovalovb, Yu.B. (2012) Refinement of the crystal structures of synthetic nickel-and cobalt-bearing tourmalines. Crystallography Reports, 57, 57–63.CrossRefGoogle Scholar
Shannon, R.D. (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chaleogenides. Acta Crystallographica, A32, 751–767.CrossRefGoogle Scholar
Sheldrick, G.M. (2013) SHELXL-2013. University of Göttingen, Germany.Google Scholar
Skogby, H., Bosi, F. and Lazor, P. (2012) Short-range order in tourmaline: a vibrational spectroscopic approach to elbaite. Physics and Chemistry of Minerals, 39, 811–816.CrossRefGoogle Scholar
Smith, G. (1978) A reassessment of the role of iron in the 5,000-30.000 cm-1 region of the electronic absorption spectra of tourmaline. Physics and Chemistry of Minerals, 3, 343–373.CrossRefGoogle Scholar
Taran, M.N., Lebedev, A.S. and Platonov, A.N. (1993) Optical absorption spectroscopy of synthetic tourmalines. Physics and Chemistry of Minerals, 20, 209–220.CrossRefGoogle Scholar
Vereshchagin, O.S., Rozhdestvenskaya, I.V., Frank-Kamenetskaya, O.V., Zolotarev, A.A. and Mashkovtsev, R.I. (2013) Crystal chemistry of Cubearing tourmalines. American Mineralogist, 98, 1610–1616.CrossRefGoogle Scholar
Wright, S.E., Foley, J.A. and Hughes, J.M. (2000) Optimization of site occupancies in minerals using quadratic programming. American Mineralogist, 85, 524–531.CrossRefGoogle Scholar
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