Plášilite
Plášilite | |
---|---|
General | |
Category | Sulfate mineral |
Formula (repeating unit) | Na(UO2)(SO4)(OH)•2H2O |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | P21/c |
Unit cell | a = 8.71, b = 13.84, c = 7.05 [Å], β = 112.13° (approximated) |
Identification | |
Color | Greenish yellow |
Crystal habit | prismatic |
Cleavage | {010} and {001}, perfect |
Tenacity | Brittle |
Mohs scale hardness | 2-3 |
Luster | Vitreous |
Streak | White |
Diaphaneity | Transparent |
Density | 3.73 (calculated) (approximated) |
Optical properties | Biaxal (+) |
Refractive index | nα=1.56, nβ=1.58, nγ=1.61 (approximated) |
Pleochroism | ~Colourless (X), very pale yellow (Y), pale yellow (Z) |
2V angle | 88o (measured) |
Ultraviolet fluorescence | Bluish-white |
Other characteristics | ![]() |
References | [1][2] |
Plášilite is a very rare uranium mineral with the formula Na2(UO2)(SO4)2•3H2O.[1][2] Chemically related minerals include , belakovskiite, meisserite, fermiite and oppenheimerite.[3][4][5][6][7] Most of these uranyl sulfate minerals were originally found in the Blue Lizard mine, San Juan County, Utah, US.[8] The mineral is named after Czech crystallographer Jakub Plášil.[2]
Association and origin[]
Plášilite is associated with other sulfate minerals: , johannite, blödite, brochantite, chalcanthite, gypsum, hexahydrite, manganoblödite, and tamarugite. Non-sulfate coexisting minerals include atacamite, calcite, dickite and gerhardtite. Plášilite is secondary in origin, being the product of weathering of the primary uranium mineral, uraninite.[1]
Crystal structure[]
The crystal structure of plášilite is of a new type. Its building blocks are:[1]
- (UO2)2(SO4)2(OH)2 sheets, with a charge 2-, parallel to (010), of a phosphuranylite topology
- edge-sharing NaO2(H2O)4 polyhedra, parallel to [001]
The sodium-bearing polyhedra link the uranyl-sulfate sheets. It terms of sheet geometry, crystal structure of plášilite is similar to that of .[1]
References[]
- ^ a b c d e Kampf, A.R., Kasatkin, A.V., Čejka, J., and Marty, J., 2015. Plášilite, Na(UO2)(SO4)(OH)·2H2O, a new uranyl sulfate mineral from the Blue Lizard mine, San Juan County, Utah, USA. Journal of Geosciences 60, 1-10
- ^ a b c "Plášilite: Plášilite mineral information and data". Mindat.org. Retrieved 2016-03-10.
- ^ "Natrozippeite: Natrozippeite mineral information and data". Mindat.org. Retrieved 2016-03-10.
- ^ "Belakovskiite: Belakovskiite mineral information and data". Mindat.org. Retrieved 2016-03-10.
- ^ "Meisserite: Meisserite mineral information and data". Mindat.org. Retrieved 2016-03-10.
- ^ "Fermiite: Fermiite mineral information and data". Mindat.org. Retrieved 2016-03-10.
- ^ "Oppenheimerite: Oppenheimerite mineral information and data". Mindat.org. Retrieved 2016-03-10.
- ^ "Blue Lizard Mine, Chocolate Drop, Red Canyon, White Canyon District, San Juan Co., Utah, USA - Mindat.org". Mindat.org. Retrieved 2016-03-10.
- Uranium(VI) minerals
- Sulfate minerals
- Sodium minerals
- Monoclinic minerals
- Minerals in space group 14
- Sulfate mineral stubs