Cerianite-(Ce)
| Cerianite-(Ce) | |
|---|---|
.jpg?lang=en) Yellow powder of the very rare mineral cerianite-(Ce) from Morro do Ferro, Caldas, Minas Gerais, Brazil. | |
| General | |
| Category | Oxide |
| Formula (repeating unit) | (Ce,Th)O 2 |
| IMA symbol | Cei-Ce[1] |
| Crystal system | Isometric |
| Crystal class | Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m) |
| Space group | Fm3m |
| Unit cell | a = 5.42 Å; Z = 4 |
| Identification | |
| Color | Dark greenish amber-yellow, yellow, buff |
| Crystal habit | octahedra; earthy, massive |
| Diaphaneity | Translucent or transparent |
| Density | 7.20 (synth. material, calc.; approximated) |
| Other characteristics |  Radioactive |
| References | [2][3][4] |
Cerianite-(Ce) is a relatively rare oxide mineral, belonging to uraninite group with the formula (Ce,Th)O
2.[4][5] It is one of a few currently known minerals containing essential tetravalent cerium, the other examples being stetindite and dyrnaesite-(La).[6][7]
Occurrence and association
Cerianite-(Ce) is associated with alkaline rocks, mostly nepheline syenites.[3] It may be found in carbonatites.[4] Cerianite-(Ce) associates with minerals of the apatite group, bastnäsite-group minerals, calcite, feldspar, "fluocerite", "hydromica", ilmenite, nepheline, magnetite, "törnebohmite" and tremolite.[3] It is the most simple cerium mineral known.[4]
Notes on chemistry
Beside thorium cerianite-(Ce) may contain trace niobium, yttrium, lanthanum, ytterbium, zirconium and tantalum.[3]
Crystal structure
For details on crystal structure see cerium(IV) oxide. Both ceria and thoria have a fluorite structure.
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.
- ^ Mineralienatlas
- ^ a b c d "Cerianite-(Ce) - Handbook of Mineralogy" (PDF). Handbookofmineralogy.org. Retrieved 2016-03-04.
- ^ a b c d "Cerianite-(Ce): Cerianite-(Ce) mineral information and data". Mindat.org. Retrieved 2016-03-04.
- ^ Graham, A.R., 1955. Cerianite CeO2: a new rare-earth oxide mineral. American Mineralogist 40, 560-564
- ^ "Stetindite: Stetindite mineral information and data". Mindat.org. Retrieved 2016-03-04.
- ^ "Dyrnaesite-(La): Dyrnaesite-(La) mineral information and data". Mindat.org. Retrieved 2016-03-04.