| Cerianite-(Ce) | |
| Category: | Oxide |
| Imasymbol: | Cei-Ce[1] |
| System: | Isometric |
| Class: | Hexoctahedral (mm) H-M symbol: (4/m 2/m) |
| Symmetry: | Fmm |
| Unit Cell: | a = 5.42 Å; Z = 4 |
| Color: | Dark greenish amber-yellow, yellow, buff |
| Habit: | octahedra; earthy, massive |
| Diaphaneity: | Translucent or transparent |
| Density: | 7.20 (synth. material, calc.; approximated) |
| Other: | Radioactive |
| References: | [2] |
Cerianite-(Ce) is a relatively rare oxide mineral, belonging to uraninite group with the formula .[3] [4] It is one of a few currently known minerals containing essential tetravalent cerium, the other examples being stetindite and dyrnaesite-(La).[5] [6]
Cerianite-(Ce) is associated with alkaline rocks, mostly nepheline syenites.[7] 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.[7] It is the most simple cerium mineral known.
Beside thorium cerianite-(Ce) may contain trace niobium, yttrium, lanthanum, ytterbium, zirconium and tantalum.[7]
For details on crystal structure see cerium(IV) oxide. Both ceria and thoria have a fluorite structure.