Uranpyrochlore (of Hogarth 1977) | |
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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 |
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References | [1] [2] |
Uranpyrochlore (of Hogarth 1977), also known as ellsworthite or betafite ( Ca, U)2( Ti, Nb, Ta)2 O6(O H), 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]
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]
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]