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New data on welshite, e.g. Ca2Mg3.8Mn0.62+Fe0.12+Sb1.55+O2[Si2.8Be1.7Fe0.653+Al0.7As0.17O18], an aenigmatite-group mineral

Published online by Cambridge University Press:  05 July 2018

E. S. Grew ,
U. Hålenius ,
M. Kritikos  and
C. K. Shearer
E. S. Grew*
Affiliation:
Department of Geological Sciences, University of Maine, 5790 Bryand Center, Orono, Maine 04469-5790, USA
U. Hålenius
Affiliation:
Department of Mineralogy, Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden
M. Kritikos
Affiliation:
Division of Structural Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
C. K. Shearer
Affiliation:
Institute of Meteoritics, University of New Mexico, Albuquerque, New Mexico 87131, USA
*
*E-mail: esgrew@maine.maine.edu
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Abstract

Electron and ion microprobe data on two samples of welshite from the type locality of Långban, Sweden, gave analytical totals of 99.38–99.57 wt.% and BeO contents of 4.82–5.11 wt.%, corresponding to 1.692–1.773 Be/20 O. Mössbauer and optical spectra of one of these samples gave [iv]Fe3+/ΣFe = 0.91, [vi]Fe2+/ΣFe = 0.09, and no evidence of Mn3+. The resulting formula for this sample is Ca2Mg3.8Mn0.62+Fe0.12+Sb1.55+O2[Si2.8Be1.7Fe0.653+Al0.7As0.17O18, and that for the second sample, Ca2Mg3.8Mn0.12+Fe0.12+Fe0.83+Sb1.25+O2[Si2.8Be1.8Fe0.653+Al0.5As0.25O18], is related by the substitution involving tetrahedral and octahedral sites: 0.59[vi,iv](Fe,Al)3+ ≈ 0.42[vi](Mg,Mn,Fe)2+ + 0.21([vi]Sb,[iv]As)5+, i.e. 3[vi,iv]M3+ = 2[vi]M2+ + [vi,iv]M5+. Welshite is distinctive among aenigmatite-group minerals in the high proportion of Fe3+ in tetrahedral coordination and is unique in its Be content, substantially exceeding 1Be per formula unit. Given the cation distributions in other minerals related to aenigmatite, we think it is reasonable to assume that at least one tetrahedral site is >50% occupied by Be and that one octahedral site is >50% occupied by Sb, so that welshite should be retained as a distinct species with its own name in the aenigmatite group.

Keywords

welshiteaenigmatite groupLångban depositSweden
Type
Research Article
Information
Mineralogical Magazine , Volume 65 , Issue 5 , October 2001 , pp. 665 - 674
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2001

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References

Andreozzi, G., Hålenius, U. and Skogby, H. (2001) Spectroscopic active IVFe3+-VIFe3+ clusters in spinel-magnesioferrite solid solution crystals: a potential monitor for ordering in oxide spinels. Phys. Chem. Miner., 28, 435–44.CrossRefGoogle Scholar
Barbier, J., Grew, E.S., Moore, P.B. and Su, S.-C. (1999) Khmaralite, a new beryllium-bearing mineral related to sapphirine: A superstructure resulting from partial ordering of Be, Al and Si on tetrahedral sites. Amer. Mineral., 84, 1650–60.CrossRefGoogle Scholar
Barbier, J., Grew, E.S., Yates, M.G. and Shearer, C.K. (2001) Beryllium minerals related to aenigmatite. Geol. Assoc. Canada, Mineral. Assoc. Canada, Joint Annual Meeting, Abstracts Volume. 26, 7.Google Scholar
Barbier, J., Grew, E.S., Hålenius, E., Hålenius, U. and Yates, M.G. (submitted) The role of iron and cation order in the crystal chemistry of surinamite, (Mg,Fe2+)3(Al,Fe3+)3O[AlBeSi3O15]: A crystal structure, Mössbauer spectroscopic, and optical spectroscopic study. Amer. Mineral. Google Scholar
Bonaccorsi, E., Merlino, S. and Pasero, M. (1990) Rhönite: structural and microstructural features, crystal chemistry and polysomatic relationships. Eur. J. Mineral., 2, 203–18.CrossRefGoogle Scholar
Burns, R.G. (1993) Mineralogical Applications of Crystal Field Theory, 2nd edition. Cambridge University Press, Cambridge, UK.CrossRefGoogle Scholar
Cannillo, E., Mazzi, F., Fang, J.H., Robinson, P.D. and Ohya, Y. (1971) The crystal structure of aenigmatite. Amer. Mineral., 56, 427–46Google Scholar
Christy, A.G., Tabira, Y., Hölscher, A., Grew, E.S. and Schreyer, W. (2000) Synthetic beryllian sapphirine: Structural characterization. Geol. Soc. Amer. Abstracts with Programs. 32(7), A–54.Google Scholar
Christy, A.G., Tabira, A., Hölscher, A., Grew, E.S. and Schreyer, W.F. (in press) Synthesis of beryllian sapphirine in the system MgO-BeO-Al2O3-SiO2-H2O, mechanisms for beryllium incorporation in silicates, and comparison with naturally occurring beryllian sapphirine and khmaralite. Amer. Mineral. Google Scholar
Coey, J.M.D. (1984) Mössbauer spectroscopy of silicate minerals. Pp. 443–509 in: Modern Inorganic Chemistry; Mö ssbauer Spectroscopy Applied to Inorganic Chemistry (Long, G.J., editor). Plenum Press, New York.Google Scholar
Cosca, M.A., Rouse, R.R. and Essene, E.J. (1988) Dorrite [Ca2(Mg2Fe4 3+)(Al4Si2)O20], a new member of the aenigmatite group from a pyrometamorphic melt-rock. Amer. Mineral., 73, 1440–8.Google Scholar
Deer, W.A., Howie, R.A. and Zussman, J. (1978) Rock-Forming Minerals, Single-Chain Silicates. Volume 2A, 2nd edition. Longman, London.Google Scholar
Dunn, P.J, Peacor, D.R., Criddle, A.J. and Stanley, C.J. (1988) Filipstadite, a new Mn-Fe3+-Sb derivative of spinel, from Långban, Sweden. Amer. Mineral., 73, 413–9.Google Scholar
Dyar, M.D., Wiedenbeck, M., Robertson, D., Cross, L.R., Delaney, J.S., Ferguson, K., Francis, C.A., Grew, E.S., Guidotti, C.V., Hervig, R.L., Hughes, J.M., Husler, J., Leeman, W., McGuire, A.V., Rhede, D., Rothe, H., Paul, R.L., Richard, I. and Yates, M. (in press) Reference minerals for microanalysis of light elements. Geostandards Newsletter. Google Scholar
Eggleton, R.A. (1991) Gladstone-Dale constants for the major elements in silicates: Coordination number, polarizability, and the Lorentz-Lorentz relation. Canad. Mineral., 29, 525–32.Google Scholar
Grauch, R.I., Lindahl, I., Evans, H.T. Jr., Burt, D.M., Fitzpatrick, J.J., Foord, E.E., Graff, P.-R. and Hysingjord, J. (1994) Høgtuvaite, a new beryllian member of the aenigmatite group from Norway, with new X-ray data on aenigmatite. Canad. Mineral., 2, 439–48.Google Scholar
Grew, E.S., McGee, J.J., Yates, M.G., Peacor, D.R., Rouse, R.C., Huijsmans, J.P.P., Shearer, C.K., Wiedenbeck, M., Thost, D.E. and Su, S.-C. (1998) Boralsilite (Al16B6Si2O37): A new mineral related to sillimanite from pegmatites in granulite-facies rocks. Amer. Mineral., 83, 638–51CrossRefGoogle Scholar
Grew, E.S., Yates, M.G., Barbier, J., Shearer, C.K., Sheraton, J.W., Shiraishi, K. and Motoyoshi, Y. (2000) Granulite-facies beryllium pegmatites in the Napier Complex in Khmara and Amundsen Bays, western Enderby Land, East Antarctica. Polar Geoscience, 13, 1–40.Google Scholar
Hamilton, J.D.G., Hoskins, B.F., Mumme, W.G., Borbidge, W.E. and Montague, M.A. (1989) The crystal structure and crystal chemistry of Ca2.3Mg0.8Al1.5Si1.1Fe8.3O20 (SFCA): solid solution limits and selected phase relationships of SFCA in the SiO2–Fe2O3–CaO(–Al2O3) system. Neues Jahrb. Mineral. Abh., 161, 1–26.Google Scholar
Holtstam, D. and Larsson, A.-K. (2000) Tegengrenite, a new rhombohedral spinel-related Sb mineral from the Jakobsberg Fe-Mn deposit, Värmland, Sweden. Amer. Mineral., 85, 1315–20.CrossRefGoogle Scholar
Holtstam, D., Nysten, P. and Gatedal, K. (1998) Parageneses and compositional variations of Sb oxymine rals from Långban- type deposit s in Värmland, Sweden. Mineral. Mag., 62, 395–407.CrossRefGoogle Scholar
Hughes, J.M., Ertl, A., Dyar, M.D., Grew, E.S., Shearer, C.K., Yates, M.G. and Guidotti, C.V. (2000) Tetrahedrally coordinated boron in a tourmaline: Boron-rich olenite from Stoffhütte, Koralpe, Austria. Canad. Mineral., 38, 861–8.CrossRefGoogle Scholar
Jernberg, P. and Sundqvist, B. (1983) A Versatile Mössbauer Analysis Program. Uppsala University, Institute of Physics (UUIP-1090).Google Scholar
Kunzmann, T. (1999) The aenigmatite-rhönite mineral group. Eur. J. Mineral., 11, 743–56.CrossRefGoogle Scholar
Machin, M.P. and Süsse, P. (1974) Serendibite: a new member of the aenigmatite structure group. Neues Jahrb. Mineral. Monatsh., 435-41.Google Scholar
Magnusson, N.H. (1930) The iron and manganese ores of the Långban district. Sveriges Geol. Undersökning Avhand., Ser. Ca., 23, 1–111 (in Swedish with extended English summary).Google Scholar
Mandarino, J.A. (1981) The Gladstone-Dale relationship: Part IV. The compatibility concept and its application. Canad. Mineral., 19, 441–50.Google Scholar
Merlino, S. (1972) X-ray crystallography of krinovite. Z. Kristallogr. 136, 81–8.CrossRefGoogle Scholar
Moore, P.B. (1967) Eleven new minerals from Långban, Sweden. Canad. Mineral., 9, 301 (abstract).Google Scholar
Moore, P.B. (1968 a) Contributions to Swedish mineralogy. II. Melanostibite and manganostibite, two unusual antimony minerals. The identity of ferrostibian with långbanite. Arkiv. Mineral. Geol. 4, 449–58.Google Scholar
Moore, P.B. (1968 b) Substitution of the type (Sb0.5 5+Fe0.5 3+) > (Ti4+): The crystal structure of melanostibite. Amer. Mineral., 53, 1104–9.Google Scholar
Moore, P.B. (1970 a) Manganostibite: A novel cubic close-packed structure type. Amer. Mineral., 55, 1489–99.Google Scholar
Moore, P.B. (1970 b Mineralogy & chemistry of Långban- type deposits in Bergslagen, Sweden. Mineral. Record., 1, 154–72.Google Scholar
Moore, P.B. (1978) Welshite, Ca2Mg4Fe3+Sb5+O2 [Si4Be2O18], a new member of the aenigmatite group. Mineral. Mag., 42, 129–32.CrossRefGoogle Scholar
Moore, P.B. and Araki, T. (1983) Surinamite, ca. Mg3Al4Si3BeO16: its crystal structure and relation to sapphirine, ca. Mg2.8Al7.2Si1.2BeO16 . Amer. Mineral., 68, 804–10.Google Scholar
Nickel, E.H. and Grice, J.D. (1998) The IMA Commission on New Minerals and Mineral Names: Procedures and guidelines on mineral nomenclature, 1998. Canad. Mineral., 36, 913–26.Google Scholar
Ottolini, L. and Hawthorne, F.C. (1999) An investigation of SIMS matrix effects on H, Li and B ionization in tourmaline. Eur. J. Mineral., 11, 679–90.CrossRefGoogle Scholar
Pouchou, J.L. and Pichoir, F. (1984) A new model for quantitative X-ray micro-analysis. I. Application to the analysis of homogeneous samples. La Recherche Aérospatiale, 3, 13–36.Google Scholar
Rossman, G.R. (1996) Why hematite is red; correlation of optical absorption intensities and magnetic moments of Fe3+ minerals. Pp. 23–7 in: Mineral Spectroscopy; A Tribute to Roger G. Burns (Dyar, M.D., McCammon, C. and Schaefer, M.W., editors). Special Publication Series 2. The Geochemical Society, University Park, Washington, D.C. Google Scholar
Smith, G., Hålenius, U., Annersten, H. and Ackermann, L. (1983) Optical and Mössbauer spectra of manganese-bearing phlogopites: Fe3+ IV–Mn2+ VI pair absorption as the origin of reverse pleochroism. Amer. Mineral. 68, 759–68.Google Scholar
Walenta, K. (1969) Zur Kristallographie des Rhönits. Z. Kristallogr., 130, 214–30.CrossRefGoogle Scholar
Yakubovich, O.V., Malinovskii, Yu.A. and Polyakov, V.O. (1990) Crystal structure of makarochkinite. Sov. Phys. Crystallogr., 35, 818–22.Google Scholar