| Abenakiite-(Ce) | |
|---|---|
 | |
| General | |
| Category | Silicate, cyclosilicate |
| Formula (repeating unit) | Na26Ce6(SiO3)6(PO4)6(CO3)6(SO2)O |
| IMA symbol | Abk-Ce |
| Strunz classification | 9.CK.10 |
| Crystal system | Trigonal |
| Crystal class | Rhombohedral (3) H-M symbol: (3) |
| Space group | R3 |
| Unit cell | a = 16.02, c = 19.76 , Z = 3 |
| Identification | |
| Colour | Pale brown, to dark brown |
| Crystal habit | Euhedral Crystals - Occurs as well-formed crystals showing good external form. |
| Cleavage | {0001}, poor |
| Fracture | Conchoidal |
| Mohs scale hardness | 4–5 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Transparent |
| Specific gravity | 3.32 gm/cc. |
| Density | 3.21 |
| Optical properties | Uniaxial (−) |
| Refractive index | nω=1.59, nε=1.57 |
| Other characteristics | Radioactive |
| References | |
Abenakiite-(Ce) is a mineral of sodium, cerium, neodymium, lanthanum, praseodymium, thorium, samarium, oxygen, sulfur, carbon, phosphorus, and silicon with a chemical formula Na26Ce6(SiO3)6(PO4)6(CO3)6(SO2)O. The silicate groups may be given as the cyclic Si6O18 grouping. The mineral is named after the Abenaki, an Algonquian Indian tribe of New England. Its Mohs scale rating is 4 to 5.
Occurrence and association
Abenakiite-(Ce) was discovered in a sodalite syenite xenolith at Mont Saint-Hilaire, Québec, Canada, together with aegirine, eudialyte, manganoneptunite, polylithionite, serandite, and steenstrupine-(Ce).
Notes on chemistry and relation to other species
Combination of elements in abenakiite-(Ce) is unique. Somewhat chemically similar mineral is steenstrupine-(Ce). The hyper-sodium abenakiite-(Ce) is also unique in supposed presence of sulfur dioxide ligand. With a single grain (originally) found, abenakiite-(Ce) is extremely rare.
Crystal structure
In the crystal structure, described as a hexagonal net, of abenakiite-(Ce) there are:
- chains of NaO7 polyhedra, connected with PO4 groups
- columns with six-membered rings of NaO7, and NaO7-REEO6, and SiO4 polyhedra (REE – rare earth elements)
- CO3 groups, NaO6 octahedra, and disordered SO2 ligands within the columns
See also
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.
- https://webmineral.com/data/Abenakiite-(Ce).shtml
- https://webmineral.com/data/Abenakiite-(Ce).shtml
- ^ McDonald, A.M.; Chao, G.Y.; Grice, J.D. (1994). "Abenakiite-(Ce), a new silicophosphate carbonate mineral from Mont Saint-Hilaire, Quebec: Description and structure determination" (PDF). The Canadian Mineralogist. 32: 843–854.
- ^ "Abenakiite-(Ce)". mindat.org. Retrieved 2024-05-25.
- "[International Mineralogical Association] : List of Minerals – IMA". Ima-mineralogy.org. Retrieved 2016-03-12.
External links
Media related to Abenakiite-(Ce) at Wikimedia Commons- Mindat.org
- Webmineral.org
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