Belakovskiite | |
---|---|
General | |
Category | Sulfate mineral |
Formula (repeating unit) | Na7(UO2)(SO4)4(SO3OH)(H2O)3 |
IMA symbol | Bkk[1] |
Crystal system | Triclinic |
Crystal class | Pinacoidal (1) (same H-M symbol) |
Space group | P1 |
Unit cell | a = 5.46, b = 11.33, c = 18.42 [Å], α = 104.77°, β = 90.09°, γ = 96.77° (approximated); Z = 2 |
Identification | |
Color | Yellow-green |
Crystal habit | fibrous |
Cleavage | None |
Tenacity | Brittle |
Mohs scale hardness | 2 |
Luster | Vitreous |
Streak | White |
Diaphaneity | Transparent |
Density | 3.31 (calculated); 3.23 (measured) |
Optical properties | Biaxal (+) |
Refractive index | nα=1.50, nβ=1.51, nγ=1.52 (approximated) |
Pleochroism | None |
2V angle | 88o (calculated) |
Other characteristics | Radioactive |
References | [2][3][4] |
Belakovskiite is a very rare uranium mineral with the formula Na7(UO2)(SO4)4(SO3OH)(H2O)3.[2][3] 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.[2]
Belakovskiite is associated with other sulfate minerals: meisserite, blödite, ferrinatrite, kröhnkite, and metavoltine.[2] This association is found as efflorescences on a sandstone associated with uranium mineralization.[4]
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.[2]