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Georgbarsanovite

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Mineral of the eudialyte group
Georgbarsanovite
Georgbarsanovite
General
CategorySilicate mineral, Cyclosilicate
Formula
(repeating unit)
Na12(Mn,Sr,REE)3Ca6Fe3Zr3NbSi25O76Cl2·H2O (original form)
IMA symbolGba
Strunz classification9.CO.10 (10 ed)
8/E.23-15 (8 ed)
Dana classification64.1.2.2
Crystal systemTrigonal
Crystal classDitrigonal pyramidal (3m)
(same H-M symbol)
Space groupR3m
Unit cella = 14.26, c = 29.95  (approximated); Z = 3
Identification
ColorYellow-green
Crystal habitpseudo-octahedra
CleavageNo
FractureUneven
TenacityBrittle
LusterVitreous
StreakWhite
DiaphaneityTransparent
Optical propertiesUniaxial (-)
Refractive indexnω 1.64, nε=1.63 (approximated)
Pleochroismgreen to pale yellow
Common impuritiesF, K, Y
References

Georgbarsanovite is a very rare mineral of the eudialyte group, formerly known under unaccepted name as barsanovite, with formula Na12(Mn,Sr,REE)3Ca6Fe3Zr3NbSi(Si3O9)2(Si9O27)2O4Cl2·H2O. The original formula was extended to show the presence of cyclic silicate groups and the domination of silicon at the M4 site. "REE", standing for rare earth elements, is dominated by cerium. Georgbarsanovite is characterized in dominance of manganese at the N4 site. It also differs from most other accepted group representatives in its colour. The mineral was found in nepheline pegmatite near Petrelius River, Khibiny massif, Kola Peninsula, Russia. It is named after Russian mineralogist Georg Barsanov.

Notes on chemistry

Georgbarsanovite contains admixtures of fluorine, potassium and yttrium, with traces of titanium, hafnium, and barium.

References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Mindat, http://www.mindat.org/min-27506.html
  3. ^ Khomyakov, A.P., Nechelyustov, G.N., Ekimenkova, I.A., and Rastsvetayeva, R.K., 2005. Georgbarsanovite, Na12(Mn,Sr,REE)3Ca6Fe3Zr3NbSi25O76Cl2·H2O, a mineral species of the eudialyte group: revalidation of barsanovite and the new name of the mineral. Zapiski Rossiyskogo Mineralogicheskogo Obshchestva 134(6), 47-57 (in Russian, with English abstract)
  4. Johnsen, O., Ferraris, G., Gault, R.A., Grice, D.G., Kampf, A.R., and Pekov, I.V., 2003. The nomenclature of eudialyte-group minerals. The Canadian Mineralogist 41, 785-794


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