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Proshchenkoite-(Y) from Russia - a new mineral species in the vicanite group: descriptive data and crystal structure

Raade, G.; Grice, J. D.; Erambert, M.; Kristiansson, Per LU and Witzke, T. (2008) In Mineralogical Magazine 72(5). p.1071-1082
Abstract
A REE-bearing fluorosilicate from the Tommot REE-Nb deposit in Yakutia, Russia, described without a name in 1966, is characterized here as a new species, proshchenkoite-(Y), of the vicanite group of borosilicates. Wavelength-dispersive electron probe analyses gave the following empirical formula: (Y3.70REE7.54Ca1.55Na1.16Mn0.77Th0.10Pb0.01)(Sigma 14.83)(Fe0.832+M0.15Ti0.02)(Sigma 1.00)Ca-1.00 (P0.70Si0.26As0.04)(Sigma 1.00)Si6.05B3.20(O34.55F13.45)(Sigma 48). Boron was analysed with a nuclear microprobe method based on the nuclear reaction B-11(p,alpha)2 alpha. The simplified formula is (Y,REE,Ca,Na,Mn)(15) (Fe2+,Mn)Ca(P,Si)Si6B3O34F14. The mineral is trigonal, R3m, with a = 10.7527(7) angstrom, c = 27.4002(18) angstrom, V = 2743.6(6)... (More)
A REE-bearing fluorosilicate from the Tommot REE-Nb deposit in Yakutia, Russia, described without a name in 1966, is characterized here as a new species, proshchenkoite-(Y), of the vicanite group of borosilicates. Wavelength-dispersive electron probe analyses gave the following empirical formula: (Y3.70REE7.54Ca1.55Na1.16Mn0.77Th0.10Pb0.01)(Sigma 14.83)(Fe0.832+M0.15Ti0.02)(Sigma 1.00)Ca-1.00 (P0.70Si0.26As0.04)(Sigma 1.00)Si6.05B3.20(O34.55F13.45)(Sigma 48). Boron was analysed with a nuclear microprobe method based on the nuclear reaction B-11(p,alpha)2 alpha. The simplified formula is (Y,REE,Ca,Na,Mn)(15) (Fe2+,Mn)Ca(P,Si)Si6B3O34F14. The mineral is trigonal, R3m, with a = 10.7527(7) angstrom, c = 27.4002(18) angstrom, V = 2743.6(6) angstrom(3), Z = 3. The crystal structure was refined to R1 = 0.042 for 1819 observed reflections. Proshchenkoite-(Y) is isostructural with okanoganite-(Y), vicanite-(Ce) and hundholmenite-(Y), and the differences in site occupancies are discussed. The strongest six reflections of the X-ray powder-diffraction pattern [d(obs) in angstrom, (I), (hkl)] are: 4,441, (36), (202); 3.144, (77), (214); 3.028, (45), (009); 2.968, (100), (027); 1.782, (32), (330); and 1.713, (32), (1.2.14). The mineral is optically uniaxial (-) with omega 1.734(2) and epsilon 1.728(2). The Mohs hardness is about 5; density measured on material subject to incipient metarnictization is 4.72 g/cm(3), as compared to D-calc = 4.955 g/cm(3). The result of electron microprobe analyses of alleged okanoganite-(Y) from the type locality in Okanogan County, Washington, USA, is also presented. We find here also that P > Si at one of the sites, whereas the analytical data of Boiocchi et al. (2004) indicate Si > P. Consequently, the mineral we have analysed is the P analogue of okanoganite-(Y), another new species. (Less)
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organization
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type
Contribution to journal
publication status
published
subject
keywords
nuclear microprobe, electron-microprobe data, REE borosilicate, group, vicanite, okanoganite-(Y), proshchenkoite-(Y), new mineral species, data, crystal structure, Tommot REE-Nb deposit, Russia
in
Mineralogical Magazine
volume
72
issue
5
pages
1071 - 1082
publisher
Mineralogical Society of Great Britain and Ireland
external identifiers
  • wos:000265132100007
  • scopus:64549159416
ISSN
0026-461X
DOI
10.1180/minmag.2008.072.5.1071
language
English
LU publication?
yes
id
6d114601-ef64-42c8-bb61-c7471198bc13 (old id 1399273)
date added to LUP
2009-05-28 13:29:00
date last changed
2017-01-01 04:25:05
@article{6d114601-ef64-42c8-bb61-c7471198bc13,
  abstract     = {A REE-bearing fluorosilicate from the Tommot REE-Nb deposit in Yakutia, Russia, described without a name in 1966, is characterized here as a new species, proshchenkoite-(Y), of the vicanite group of borosilicates. Wavelength-dispersive electron probe analyses gave the following empirical formula: (Y3.70REE7.54Ca1.55Na1.16Mn0.77Th0.10Pb0.01)(Sigma 14.83)(Fe0.832+M0.15Ti0.02)(Sigma 1.00)Ca-1.00 (P0.70Si0.26As0.04)(Sigma 1.00)Si6.05B3.20(O34.55F13.45)(Sigma 48). Boron was analysed with a nuclear microprobe method based on the nuclear reaction B-11(p,alpha)2 alpha. The simplified formula is (Y,REE,Ca,Na,Mn)(15) (Fe2+,Mn)Ca(P,Si)Si6B3O34F14. The mineral is trigonal, R3m, with a = 10.7527(7) angstrom, c = 27.4002(18) angstrom, V = 2743.6(6) angstrom(3), Z = 3. The crystal structure was refined to R1 = 0.042 for 1819 observed reflections. Proshchenkoite-(Y) is isostructural with okanoganite-(Y), vicanite-(Ce) and hundholmenite-(Y), and the differences in site occupancies are discussed. The strongest six reflections of the X-ray powder-diffraction pattern [d(obs) in angstrom, (I), (hkl)] are: 4,441, (36), (202); 3.144, (77), (214); 3.028, (45), (009); 2.968, (100), (027); 1.782, (32), (330); and 1.713, (32), (1.2.14). The mineral is optically uniaxial (-) with omega 1.734(2) and epsilon 1.728(2). The Mohs hardness is about 5; density measured on material subject to incipient metarnictization is 4.72 g/cm(3), as compared to D-calc = 4.955 g/cm(3). The result of electron microprobe analyses of alleged okanoganite-(Y) from the type locality in Okanogan County, Washington, USA, is also presented. We find here also that P > Si at one of the sites, whereas the analytical data of Boiocchi et al. (2004) indicate Si > P. Consequently, the mineral we have analysed is the P analogue of okanoganite-(Y), another new species.},
  author       = {Raade, G. and Grice, J. D. and Erambert, M. and Kristiansson, Per and Witzke, T.},
  issn         = {0026-461X},
  keyword      = {nuclear microprobe,electron-microprobe data,REE borosilicate,group,vicanite,okanoganite-(Y),proshchenkoite-(Y),new mineral species,data,crystal structure,Tommot REE-Nb deposit,Russia},
  language     = {eng},
  number       = {5},
  pages        = {1071--1082},
  publisher    = {Mineralogical Society of Great Britain and Ireland},
  series       = {Mineralogical Magazine},
  title        = {Proshchenkoite-(Y) from Russia - a new mineral species in the vicanite group: descriptive data and crystal structure},
  url          = {http://dx.doi.org/10.1180/minmag.2008.072.5.1071},
  volume       = {72},
  year         = {2008},
}