Uranophane
| Uranophane | |
|---|---|
| 
 Uranophane | |
| General | |
| Category | Uranyl neso- and polysilicates | 
| Formula (repeating unit) | Ca(UO2)2[HSiO4]2·5H2O | 
| Strunz classification | 9.AK.15 | 
| Crystal system | Monoclinic | 
| Unit cell | a = 15.85 Å, b = 6.98 Å c = 6.64 Å; β = 97.45°; Z = 2 | 
| Identification | |
| Formula mass | 586.36 | 
| Color | Light yellow, lemon-yellow, honey-yellow, straw-yellow, green-yellow | 
| Crystal habit | Crystals occur as stellate needle aggregates; as fibrous crusts, and massive | 
| Crystal symmetry | Monoclinic - sphenoidal H-M symbol: (2) Space group: P 21 | 
| Cleavage | {100} Perfect | 
| Fracture | Uneven | 
| Tenacity | Brittle | 
| Mohs scale hardness | 2.5 | 
| Luster | Vitreous to pearly; waxy or dull when massive | 
| Streak | Yellowish white | 
| Diaphaneity | Translucent to subtranslucent | 
| Specific gravity | 3.81 - 3.90 | 
| Optical properties | Biaxial (-) | 
| Refractive index | nα = 1.643 nβ = 1.666 nγ = 1.669 | 
| Birefringence | δ = 0.026 | 
| Pleochroism | Weak; X = colorless; Y = pale canary-yellow; Z = canary-yellow | 
| 2V angle | 32° to 45°, measured | 
| Ultraviolet fluorescence | Weak yellow-green under both short and long UV | 
| Other characteristics | Radioactive | 
| References | [1][2][3] | 
Uranophane Ca(UO2)2(SiO3OH)2·5H2O is a rare calcium uranium silicate hydrate mineral that forms from the oxidation of uranium bearing minerals. Uranophane is also known as uranotile. It has a yellow color and is radioactive.
References
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