Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-28T18:51:16.641Z Has data issue: false hasContentIssue false
  • English
  • Français

Veblenite, K2☐2Na(Fe2+5Fe3+4Mn2+7☐)Nb3Ti(Si2O7)2(Si8O22)2O6(OH)10(H2O)3, a new mineral from Seal Lake, Newfoundland and Labrador: mineral description, crystal structure, and a new veblenite Si8O22 ribbon

Published online by Cambridge University Press:  05 July 2018

F. Cámara ,
E. Sokolova ,
F. C. Hawthorne ,
R. Rowe ,
J. D. Grice  and
K. T. Tait
F. Cámara*
Affiliation:
Dipartimento di Scienze della Terra, Università degli Studi di Torino, via Valperga Caluso 35, 10125 Torino, Italy CrisDi, Interdepartmental Centre for the Research and Development of Crystallography, Via P. Giuria 5, I-10125, Torino, Italy Department of Geological Sciences, University of Manitoba, 240 Wallace Building, 125 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
E. Sokolova
Affiliation:
Department of Geological Sciences, University of Manitoba, 240 Wallace Building, 125 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
F. C. Hawthorne
Affiliation:
Department of Geological Sciences, University of Manitoba, 240 Wallace Building, 125 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
R. Rowe
Affiliation:
Research Division, Canadian Museum of Nature, 240 McLeod St, Ottawa, ON K1P 6P4, Ontario, Canada
J. D. Grice
Affiliation:
Research Division, Canadian Museum of Nature, 240 McLeod St, Ottawa, ON K1P 6P4, Ontario, Canada
K. T. Tait
Affiliation:
Department of Natural History, Royal Ontario Museum, 100 Queens Park, Toronto, ON M5S 2C6, Ontario Canada
*
*E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Veblenite, ideally K2☐2Na(Fe2+5Fe3+4Mn2+7☐)Nb3Ti(Si2O7)2(Si8O22)2O6(OH)10(H2O)3, is a new mineral with no natural or synthetic analogues. The mineral occurs at Ten Mile Lake, Seal Lake area, Newfoundland and Labrador (Canada), in a band of paragneiss consisting chiefly of albite and arfvedsonite. Veblenite occurs as red brown single laths and fibres included in feldspar. Associated minerals are niobophyllite, albite, arfvedsonite, aegirine-augite, barylite, eudidymite, neptunite, Mn-rich pectolite, pyrochlore, sphalerite and galena. Veblenite has perfect cleavage on {001} and splintery fracture. Its calculated density is 3.046 g cm–3. Veblenite is biaxial negative with α 1.676(2), β 1.688(2), γ 1.692(2) (λ 590 nm), 2Vmeas = 65(1)°, 2Vcalc = 59.6°, with no discernible dispersion. It is pleochroic in the following pattern: X = black, Y = black, Z = orange-brown. The mineral is red-brown with a vitreous, translucent lustre and very pale brown streak. It does not fluoresce under short and long-wave UV-light. Veblenite is triclicnic, space group P, a 5.3761(3), b 27.5062(11), c 18.6972(9) Å, α 140.301(3), β 93.033(3), γ 95.664(3)°, V = 1720.96(14) Å3. The strongest lines in the X-ray powder diffraction pattern [d(Å)(I)(hkl)] are: 16.894(100)(010), 18.204(23)(01), 4.271(9)(, 040, 120), 11.661(8)(001), 2.721(3)(), 4.404(3)(, ), 4.056(3)(031, 12; , ), 3.891(2)(003).

The chemical composition of veblenite from a combination of electron microprobe analysis and structural determination for H2O and the Fe2+/Fe3+ ratio is Nb2O5 11.69, TiO2 2.26, SiO2 35.71, Al2O3 0.60, Fe2O3 10.40, FeO 11.58, MnO 12.84, ZnO 0.36, MgO 0.08, BaO 1.31, SrO 0.09, CaO 1.49, Cs2O 0.30, K2O 1.78, Na2O 0.68, H2O 4.39, F 0.22, O = F –0.09, sum 95.69 wt.%. The empirical formula [based on 20 (Al+Si) p. f. u. is (K0.53Ba0.28Sr0.03☐0.16)Σ1(K0.72Cs0.07☐1.21)Σ2(Na0.72Ca0.17☐1.11)Σ2(Fe2+5.32Fe3+4.13Mn2+5.97Ca0.70Zn0.15Mg0.07☐0.66)Σ17(Nb2.90Ti0.93Fe3+0.17)Σ4(Si19.61Al0.39)Σ20O77.01H16.08F0.38. The simplified formula is (K, Ba, ☐)3(☐, Na)2(Fe2+, Fe3+, Mn2+)17(Nb,Ti)4(Si2O7)2(Si8O22)2O6(OH)10(H2O)3. The infrared spectrum of the mineral contains the following bands (cm–1): 453, 531, 550, 654 and 958, with shoulders at 1070, 1031 and 908. A broad absorption was observed between ~3610 and 3300 with a maximum at ~3525. The crystal structure was solved by direct methods and refined to an R1 index of 9.1%. In veblenite, the main structural unit is an HOH layer, which consists of the octahedral (O) and two heteropolyhedral (H) sheets. The H sheet is composed of Si2O7 groups, veblenite Si8O22 ribbons and Nb-dominant D octahedra. This is the first occurrence of an eight-membered Si8O22 ribbon in a mineral crystal structure. In the O sheet, (Fe2+, Fe3+, Mn2+) octahedra share common edges to form a modulated O sheet parallel to (001). HOH layers connect via common vertices of D octahedra and cations at the interstitial A(1,2) and B sites. In the intermediate space between two adjacent HOH layers, the A(1) site is occupied mainly by K; the A(2) site is partly occupied by K and H2O groups, the B site is partly occupied by Na. The crystal structure of veblenite is related to several HOH structures: jinshanjiangite, niobophyllite (astrophyllite group) and nafertisite. The mineral is named in honour of David R. Veblen in recognition of his outstanding contributions to the fields of mineralogy and crystallography.

Keywords

veblenitenew mineralSeal LakeNewfoundland and LabradorCanadaelectron-microprobe analysiscrystal structureveblenite ribbonnafertisiteniobophyllitejinshanjiangite
Type
Research Article
Information
Mineralogical Magazine , Volume 77 , Issue 7 , October 2013 , pp. 2955 - 2974
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2013

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

Brown, I.D. (1981) The bond-valence method: an empirical approach to chemical structure and bonding. Pp. 1–30. in: Structure and Bonding in Crystals II (M. O’Keeffe and A. Navrotsky, editors). Academic Press, New York.Google Scholar
Cámara, F. and Sokolova, E., (2007) From structure topology to chemical composition. VI. Titanium silicates: the crystal structure and crystal chemistry of bornemanite, a group-III Ti-disilicate mineral. Mineralogical Magazine, 71, 593–610.CrossRefGoogle Scholar
Cámara, F. and Sokolova, E., (2009) From structure topology to chemical composition. X. Titanium silicates: the crystal structure and crystal chemistry of nechelyustovite, a group III Ti-disilicate mineral. Mineralogical Magazine, 73, 887–897.Google Scholar
Cámara, F., Sokolova, E., Abdu, Y., and Hawthorne, F.C. (2010) The crystal structures of niobophyllite, kupletskite-(Cs) and Sn-rich astrophyllite; revisions to the crystal chemistry of the astrophyllite-group minerals. The Canadian Mineralogist, 48, 1–16.CrossRefGoogle Scholar
Cámara, F., Sokolova, E., and Hawthorne, F.C. (2012) Kazanskyite , Ba□TiNbNa3Ti(Si2O7 ) 2O2 (OH)2(H2O)4, a Group-III Ti-disilicate mineral from the Khibiny alkaline massif, Kola Peninsula, Russia: description and crystal structure. Mineralogical Magazine, 76, 473–492.CrossRefGoogle Scholar
Ercit, T.S., Cooper, M.A. and Hawthorne, F.C. (1998) The crystal structure of vuonnemite , Na11Ti4+Nb2(Si2O7)2(PO4)2O3(F,OH), a phosphatebearing sorosilicate of the lomonosovite group. The Canadian Mineralogist, 36, 1311–1320.Google Scholar
Ferraris, G. (2008) Modular structures – the paradigmatic case of the heterophyllosilicates. Zeitschrift für Kristallographie, 223, 76–84.Google Scholar
Ferraris, G., Ivaldi, G., Khomyakov, A.P., Soboleva, S.V., Belluso, E., and Pavese, A., (1996) Nafertisite, a layer titanosilicate member of a polysomatic series including mica. European Journal of Mineralogy, 8, 241–249.CrossRefGoogle Scholar
Hawthorne, F.C. (2012) Bond topology and structuregenerating functions: graph-thoretic prediction of chemical composition and structure in polysomatic T–O–T (biopyribole) and H–O–H structures. Mineralogical Magazine, 76, 1053–1080.CrossRefGoogle Scholar
Hong, W. and Fu, P., (1982) Jinshajiangite, a new Ba- Mn-Fe-Ti-bearing silicate mineral. Geochemistry (China), 1, 458–464.Google Scholar
Khomyakov, A.P. , Ferraris, G., , Ivaldi, G., , Nechelyustov, G.N. and Soboleva, S.V. (1995) Nafertisi t e , Na3(Fe2+,Fe3+) 6[Ti 2Si12O3 4] (O,OH)7·2H2O, a new mineral with a new type of banded silicate radical. Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva, 124, 101–107. (in Russian).Google Scholar
Nickel, E.H., Rowland, J.F. and Charette, D.J. (1964) Niobophyllite-the niobium analogue of astrophyllite; a new mineral from Seal Lake, Labrador. The Canadian Mineralogist, 8, 40–52.Google Scholar
Pouchou, J.L. and Pichoir, F., (1985) ‘PAP’ j(rZ) procedure for improved quantitative microanalysis. Pp. 104–106. in: Microbeam Analysis (J.T. Armstrong, editor). San Francisco Press, San Francisco, California, USA.Google Scholar
Rowe, R. (2009) New statistical calibration approach for Bruker AXS D8 Discover microdiffractometer with Hi-Star detector using GADDS software I.D. Powder diffraction Journal, 24, 263–271.Google Scholar
Shannon, R.D. (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallographica, A32, 751–767.CrossRefGoogle Scholar
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112–122.CrossRefGoogle Scholar
Sokolova, E. (2006) From structure topology to chemical composition. I. Structural hierarchy and stereochemistry in titanium disilicate minerals. The Canadian Mineralogist, 44, 1273–1330.CrossRefGoogle Scholar
Sokolova, E. (2012) Further developments in the structure topology of the astrophyllite-group minerals. Mineralogical Magazine, 76, 863–882.CrossRefGoogle Scholar
Sokolova, E. and Hawthorne, F.C. (2004) The crystal chemistry of epistolite. The Canadian Mineralogist, 42, 797–806.CrossRefGoogle Scholar
Sokolova, E., Cámara, F., Hawthorne, F.C. and Abdu, Y., (2009) From structure topology to chemical composition. VII. Titanium silicates: the crystal structure and crystal chemistry of jinshajiangite. European Journal of Mineralogy, 21, 871–883.CrossRefGoogle Scholar
Wilson, A.J.C. (editor) (1992) International Tables for Crystallography. Volume C: Mathematical, Physical and Chemical. Kluwer Academic Publishers, Dordrecht, The Netherlands.Google Scholar
Supplementary material: File

Cámara et al. supplementary material

Structure factors

Download Cámara et al. supplementary material(File)
File 184.3 KB
Supplementary material: File

Cámara et al. supplementary material

Anisotropic displacement parameters

Download Cámara et al. supplementary material(File)
File 51.2 KB
Supplementary material: File

Cámara et al. supplementary material

CIF

Download Cámara et al. supplementary material(File)
File 192 KB