Fengchengite
Fengchengite is a rare mineral of the eudialyte group[2] with the formula Na12[ ]3(Ca,Sr)6Fe33+Zr3Si(Si25O73)(H2O,OH)3(OH,Cl)2.[3][2] The formula is simplified as it does not show the presence of cyclic silicate groups. When compared to other minerals of the group, fengchengite characterizes in the presence of ferric iron (thus similar to ikranite, mogovidite and feklichevite[2]) and essential, site-dominating vacancies. The mineral was discovered in the Saima complex near Fengcheng city in China - hence its name.[2][3]
| Fengchengite | |
|---|---|
| General | |
| Category | Cyclosilicate |
| Formula (repeating unit) | Na12[ ]3(Ca,Sr)6Fe33+Zr3Si(Si25O73)(H2O,OH)3(OH,Cl)2 |
| IMA symbol | Fcg[1] |
| Crystal system | Trigonal |
| Crystal class | Hexagonal scalenohedral (3m) H-M symbol: (3 2m) |
| Space group | R3m |
| Unit cell | a = 14.25, c = 30.03 [Å] (approximated) |
| Identification | |
| References | [2][3] |
References
- 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.
- Mindat, Fengchengite, http://www.mindat.org/min-42378.html
- Shen, G., Xu, J., Yao, P., and Li, G., 2011. Fengchengite, IMA 2007-018a. CNMNC Newsletter No. 11, December 2011, 2892; Mineralogical Magazine 75, 2887-2893
Further reading
- 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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