Soddyite is a mineral of uranium. It has yellow crystals and usually mixed with curite in oxidized uranium ores. It is named after Frederick Soddy (1877–1956), british radiochemist and physicist. It's been a valid species since 1922.[1][2][3]
| Soddyite |
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 A piece of rock from Swambo in the Democratic Republic of Congo containing yellow crystals of soddyite |
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| Category | Nesosilicates |
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Formula
(repeating unit) | (UO2)2SiO4·2H2O |
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| Strunz classification | 9.AK.05 |
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| Dana classification | 53.03.03.01 |
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| Crystal system | Orthorhombic |
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| Crystal class | Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m) |
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| Space group | F ddd |
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| Unit cell | 1,745.03 ų |
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| Color | Canary yellow to amber yellow |
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| Cleavage | Perfect on {001}, good on {111} |
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| Mohs scale hardness | 3 - 4 |
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| Luster | Vitreous, greasy, dull |
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| Streak | Yellow |
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| Diaphaneity | Transparent, translucent, opaque |
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| Density | 4.627 |
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| Optical properties | Biaxial (-) |
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| Refractive index | nα = 1.650 - 1.654, nβ = 1.685, nγ = 1.699 - 1.715 |
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| Birefringence | 0.049 - 0.061 |
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| Dispersion | Relatively weak |
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| Ultraviolet fluorescence | Weak orange yellow |
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| Other characteristics |  Radioactive |
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