Ellsworthite
| Uranpyrochlore (of Hogarth 1977) | |
|---|---|
| General | |
| Category | Pyrochlore group |
| Formula (repeating unit) | (Ca,U)2(Ti,Nb,Ta)2O6(OH) |
| Crystal system | isometric |
| Space group | Cubic 4/m 3* 2/m |
| Identification | |
| Color | amber yellow to dark brown; translucent or opaque |
| Cleavage | None |
| Fracture | conchoidal fracture |
| Mohs scale hardness | 5.5 |
| Luster | vitreous |
| Streak | yellow to brownish[1] |
| Other characteristics |  Radioactive |
| References | [1][2] |
Uranpyrochlore (of Hogarth 1977), also known as ellsworthite or betafite (Ca,U)2(Ti,Nb,Ta)2O6(OH), is a rare earth mineral mostly found in the northern parts of North America. It is a uranpyrochlore and is named after Hardy V. Ellsworth of the Canadian Geological Survey by Walker and Parsons.[3] It is a very uranium- and thorium- rich mineral, which in fact makes it slightly radioactive. Uranium makes up about 17.1% of the mineral.[4] Ellsworthite is also known as the mineral Betafite. Ellsworthite is a thorium-bearing mineral that is found mostly in Canada and Alaska. It was first discovered in Hybla, Ontario, which is now a ghost town.[2]
Composition
[edit]Ellsworthite has complex hydrous oxides of niobium, tantalum, sodium, calcium, with hydroxyl and fluorine; it may contain as much as 17% uranium.[5][1][6]
Structure
[edit]The structure of ellsworthite is cubic and has a point group of 4/m 3* 2/m. It is part of the isometric system and has the space group Fd3m. It forms into a Hexoctahedral with {110}, {100}, {113}, {233}, and {230}.[1]
Sources
[edit]- ^ a b c d "Betafite" (PDF). The Handbook of Mineralogy. Archived from the original (PDF) on 22 August 2011. Retrieved 21 October 2013.
- ^ a b Frodel, Clifford. (1958). Systematic Mineralogy of Uranium And Thorium, Geological survey bulletin 1064 pg.326-330
- ^ T. L. Walker and A. L. Parsons (1923) Ellsworthite and associated minerals from Hybla, Ontario. Contrib. Canad. Min., 1923, Univ. Toronto Stud., Geol. Ser., 16, 13-20
- ^ "A glossary of uranium- and thorium-bearing minerals / by Judith Weiss Frondel and Michael Fleischer". HathiTrust. Retrieved 2024-09-03.
- ^ Bates, R.G., Wedow Jr, H. (1953). Preliminary summary review of Thorium-Bearing mineral occurrence in Alaska. Geological Survey bulletin 202
- ^ Hogarth D.D. (1961) A study of Pyrochlore and Betafite, volume 6, issue 5. Canadian Mineralogist pg.610
- Bulletin of the National Research Council, Number 77, Physics of the Earth - I Volcanology, By the Subsidiary Committee on Volcanology, Published by the National Research Council of The National Academy of Sciences Washington, D.C., (1931)