Ichnusaite
Ichnusaite (pronounced iknusa-ait) is a very rarely found mineral.[3] Ichnusaite is a natural compound of thorium and molybdenum with the formula Th(MoO4)2·3H2O. It was discovered in Su Seinargiu, Sarroch, Cagliari, Sardegna, Italy in 2013.[2] The name is from the old Greek name of Sardinia, Ιχνουσσα, Ichnusa.[5]
This locality is also a place of discovery of the second natural thorium molybdate - nuragheite.[6]
| Ichnusaite | |
|---|---|
| General | |
| Category | Molybdate minerals |
| Formula (repeating unit) | Th(MoO4)2•3H2O |
| IMA symbol | Ich[1] |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P21/b |
| Unit cell | a = 9.68, b = 10.38 c = 9.38 [Å], β = 90.00° (approximated) Z = 4 |
| Identification | |
| Color | Colorless |
| Cleavage | {100}, perfect |
| Tenacity | Brittle |
| Luster | Pearly adamantine |
| Other characteristics |  Radioactive |
| References | [2][3][4] |
Occurrence and association
Muscovite, nuragheite, and xenotime-(Y) are the associates of ichnusaite.[2]
Notes on chemistry
Ichnusaite is chemically pure.[2]
Crystal structure
The main features of the crystal structure of ichnusaite are:[2]
- electroneutral Th(MoO4)2(H2O)2 (100) sheets
- ThO7(H2O)2 and MoO4 polyhedra polymerize to give the above sheets
- sheets are stacked along [100] and held by hydrogen bonds
Bibliography
- Orlandi, P., Biagioni, C., Bindi, L. und Nestola, F. (2013) Ichnusaite, IMA 2013- 087. CNMNC Newsletter No. 18, December 2013, page 3255; Mineralogical Magazine, 77, 3249-325
- http://rruff.geo.arizona.edu/AMS/result.php?mineral=Ichnusaite
- https://web.archive.org/web/20160521090233/http://ammin.geoscienceworld.org/content/99/10/2089
- https://arpi.unipi.it/handle/11568/638691#.Vr93OUKuAt4
- http://www.degruyter.com/dg/viewarticle/j$002fammin.2014.99.issue-10$002fam-2014-4844$002fam-2014-4844.xml
- https://www.bbc.com/news/science-environment-35569659
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.
- Orlandi, Paolo; Biagioni, Cristian; Bindi, Luca; Nestola, Fabrizio (2014-10-01). "Ichnusaite, Th(MoO4)2·3H2O, the first natural thorium molybdate: Occurrence, description, and crystal structure". American Mineralogist. 99 (10): 2089–2094. doi:10.2138/am-2014-4844. ISSN 0003-004X. S2CID 97061833. Archived from the original on 2016-05-21. Retrieved 2016-02-13.
- "Ichnusaite- Mindat.org". Mindat.org. Retrieved 2016-03-06.
- Mineralienatlas
- "Ichnusaite". www.mindat.org. Retrieved 2021-05-07.
- "Nuragheite - Mindat.org". Mindat.org. Retrieved 2016-03-06.
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