Chemistry:Georgbarsanovite
| Georgbarsanovite | |
|---|---|
 Georgbarsanovite | |
| General | |
| Category | Silicate mineral, Cyclosilicate |
| Formula (repeating unit) | Na 12(Mn,Sr,REE) 3Ca 6Fe 32+ Zr 3NbSi 25O 76Cl 2 · H2O (original form) |
| Strunz classification | 9.CO.10 (10 ed) 8/E.23-15 (8 ed) |
| Dana classification | 64.1.2.2 |
| Crystal system | Trigonal |
| Crystal class | Ditrigonal pyramidal (3m) (same H-M symbol) |
| Space group | R3m |
| Unit cell | a = 14.26, c = 29.95 [Å] (approximated); Z = 3 |
| Identification | |
| Color | Yellow-green |
| Crystal habit | pseudo-octahedra |
| Cleavage | No |
| Fracture | Uneven |
| Tenacity | Brittle |
| |re|er}} | Vitreous |
| Streak | White |
| Diaphaneity | Transparent |
| Optical properties | Uniaxial (-) |
| Refractive index | nω 1.64, nε=1.63 (approximated) |
| Pleochroism | green to pale yellow |
| Common impurities | F, K, Y |
| References | [1][2] |
Georgbarsanovite is a very rare mineral of the eudialyte group,[1] formerly known under unaccepted name as barsanovite, with formula Na
12(Mn,Sr,REE)
3Ca
6Fe
32+
Zr
3NbSi(Si
3O
9)
2(Si
9O
27)
2O
4Cl
2 · H2O.[2] The original formula was extended to show the presence of cyclic silicate groups and the domination of silicon at the M4 site.[4] "REE", standing for rare earth elements, is dominated by cerium. Georgbarsanovite is characterized in dominance of manganese at the N4 site.[2] 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.[1] It is named after Russian mineralogist Georg Barsanov.[2]
Notes on chemistry
Georgbarsanovite contains admixtures of fluorine, potassium and yttrium, with traces of titanium, hafnium, and barium.[2]
References
- ↑ 1.0 1.1 1.2 Mindat, http://www.mindat.org/min-27506.html
- ↑ 2.0 2.1 2.2 2.3 2.4 Khomyakov, A.P., Nechelyustov, G.N., Ekimenkova, I.A., and Rastsvetayeva, R.K., 2005. Georgbarsanovite, Na
12(Mn,Sr,REE)
3Ca
6Fe
32+
Zr
3NbSi
25O
76Cl
2 · 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) - ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode: 2021MinM...85..291W.
- ↑ 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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