Weeksite
| Weeksite | |
|---|---|
 | |
| General | |
| Category | Silicate mineral |
| Formula (repeating unit) | K2(UO2)2Si6O15·4(H2O) |
| Strunz classification | 9.AK.30 |
| Crystal system | Orthorhombic |
| Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Space group | Pnnb (no. 52) |
| Unit cell | a = 14.26 Å, b = 35.88 Å c = 14.2 Å; Z = 16 |
| Identification | |
| Colour | Yellow |
| Crystal habit | Occurs as acicular to elongated bladed crystals, flattened on {010}, also as radiating fibrous clusters and spherulites, pseudotetragonal |
| Cleavage | Distinct prismatic |
| Mohs scale hardness | 1 - 2 |
| Lustre | Waxy to silky |
| Streak | Yellow |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 4.1 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.596 nβ = 1.603 nγ = 1.606 |
| Birefringence | δ = 0.010 |
| Pleochroism | X = colorless; Y = pale yellow-green; Z = yellow-green |
| 2V angle | Measured: 60° |
| Other characteristics |  Radioactive greater than 70 Bq/g |
| References | [1][2][3] |
Weeksite is a naturally occurring uranium silicate mineral with the chemical formula: K2(UO2)2Si6O15•4(H2O), potassium uranyl silicate. Weeksite has a Mohs hardness of 1-2. It was named for USGS mineralogist Alice Mary Dowse Weeks (1909–1988).[2][3]
Appearance[]
Weeksite is visually similar to other uranium minerals such as carnotite and zippeite, both being encrustations that form on other rocks (usually sandstones or limestones).
Occurrence[]
Weeksite was first described in 1960 for an occurrence on Topaz Mountain, Thomas Range, Juab County, Utah.[1]
Weeksite occurs within small "opal" veins within rhyolite and agglomerates, and as encrustations in sandstones and limestones. It occurs associated with opal, chalcedony, calcite, gypsum, fluorite, uraninite, , uranophane, boltwoodite, carnotite and margaritasite.[2]
See also[]
- Mineral evolution
- List of minerals – List of minerals for which there are articles on Wikipedia
- List of minerals named after people
References[]
- ^ a b "Weeksite mineral information and data". Mindat.org. 2011-06-19. Retrieved 2012-02-10.
- ^ a b c Handbook of Mineralogy
- ^ a b Webmineral data for weeksite
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- Uranium(VI) minerals
- Potassium minerals
- Nesosilicates
- Orthorhombic minerals
- Minerals in space group 52
- Silicate mineral stubs