Coconinoite
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| Coconinoite | |
|---|---|
 | |
| General | |
| Category | Phosphate minerals |
| Formula | Fe3+2Al2(UO2)2(PO4)4(SO4)(OH)2•20(H2O) |
| IMA symbol | Coc[1] |
| Strunz classification | 8.EB.35 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | C2/c |
| Unit cell | a = 12.45(6) Å, b = 12.96(3) Å, c = 17.22(5) Å; β = 105.7°; Z = 4 |
| Identification | |
| Formula mass | 489.01 gram/mol |
| Color | Pale creamy yellow |
| Crystal habit | As lathlike to platy grains, in microcrystalline aggregates seams and crusts. |
| Mohs scale hardness | 1-2 |
| Luster | Adamantine - pearly |
| Streak | White |
| Diaphaneity | Translucent |
| Specific gravity | 2.70 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.550 nβ = 1.588 nγ = 1.590 |
| Birefringence | δ = 0.040 |
| Pleochroism | X = colorless; Y = Z = pale yellow. Orientation: Y = elongation of laths with positive elongation; Y at 8°-25° to elongation of laths with negative elongation. |
| 2V angle | Measured: 28° to 43°, Calculated: 24° |
| Other characteristics |  Radioactive |
| References | [2][3][4] |
Coconinoite is a uranium ore that was discovered in Coconino County, Arizona. It is a phosphate mineral; or uranyl phosphate mineral along with other subclass uranium U6+ minerals like blatonite, boltwoodite, metazeunerite and rutherfordine.
The chemical formula is Fe2Al2(UO2)2(PO4)4(SO4)(OH)2·20H2O.[5] The chemical formula was derived from the spectrographic analysis.[5]