| Belakovskiite | |
| Category: | Sulfate mineral |
| Formula: | Na7(UO2)(SO4)4(SO3OH)(H2O)3 |
| Imasymbol: | Bkk[1] |
| System: | Triclinic |
| Class: | Pinacoidal (same H-M symbol) |
| Symmetry: | P |
| Unit Cell: | a = 5.46, b = 11.33, c = 18.42 [Å], α = 104.77°, β = 90.09°, γ = 96.77° (approximated); Z = 2 |
| Color: | Yellow-green |
| Habit: | fibrous |
| Cleavage: | None |
| Tenacity: | Brittle |
| Mohs: | 2 |
| Luster: | Vitreous |
| Streak: | White |
| Diaphaneity: | Transparent |
| Density: | 3.31 (calculated); 3.23 (measured) |
| Opticalprop: | Biaxal (+) |
| Refractive: | nα=1.50, nβ=1.51, nγ=1.52 (approximated) |
| Pleochroism: | None |
| 2V: | 88o (calculated) |
| Other: | Radioactive |
| References: | [2] |
Belakovskiite is a very rare uranium mineral with the formula Na7(UO2)(SO4)4(SO3OH)(H2O)3.[3] [4] It is interesting in being a natural uranyl salt with hydrosulfate anion, a feature shared with meisserite.[5] Other chemically related minerals include fermiite, oppenheimerite, natrozippeite and plášilite.[6] [7] [8] [9] Most of these uranyl sulfate minerals was originally found in the Blue Lizard mine, San Juan County, Utah, US.[10] The mineral is named after Russian mineralogist Dmitry Ilych Belakovskiy.
Belakovskiite is associated with other sulfate minerals: meisserite, blödite, ferrinatrite, kröhnkite, and metavoltine. This association is found as efflorescences on a sandstone associated with uranium mineralization.
The framework of belakovskiite crystal structure is a hexavalent cluster with composition (UO2)(SO4)4(H2O). Such clusters are connected via Na-O and hydrogen bonds.