Cerianite-(Ce) | |
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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 |
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 |
Cerianite-(Ce) is a relatively rare oxide mineral, belonging to uraninite group with the formula (Ce,Th)O
2. It is one of a few currently known minerals containing essential tetravalent cerium, the other examples being stetindite and dyrnaesite-(La).
Occurrence and association
Cerianite-(Ce) is associated with alkaline rocks, mostly nepheline syenites. It may be found in carbonatites. Cerianite-(Ce) associates with minerals of the apatite group, bastnäsite-group minerals, calcite, feldspar, "fluocerite", "hydromica", ilmenite, nepheline, magnetite, "törnebohmite" and tremolite. It is the most simple cerium mineral known.
Notes on chemistry
Beside thorium cerianite-(Ce) may contain trace niobium, yttrium, lanthanum, ytterbium, zirconium and tantalum.
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
- ^ "Cerianite-(Ce) - Handbook of Mineralogy" (PDF). Handbookofmineralogy.org. Retrieved 2016-03-04.
- ^ "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.
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