| Oppenheimerite | |
| Category: | Sulfate mineral |
| Formula: | Na2(UO2)(SO4)2•3H2O |
| Imasymbol: | Ohm[1] |
| System: | Triclinic |
| Class: | Pinacoidal (same H-M symbol) |
| Symmetry: | P |
| Unit Cell: | a = 7.96, b = 8.20, c = 9.81 [Å]; α = 65.97° β = 70.28°, γ = 91.46° (approximated), Z = 2 |
| Color: | Pale greenish-yellow |
| Habit: | prismatic |
| Cleavage: | , and, good |
| Fracture: | Irregular |
| Mohs: | 2.5 |
| Luster: | Vitreous |
| Streak: | White |
| Diaphaneity: | Transparent |
| Density: | 3.36 (calculated) (approximated) |
| Opticalprop: | Biaxal (+) |
| Refractive: | nα=1.54, nβ=1.63, nγ=1.59 (approximated) |
| Pleochroism: | Very pale greenish-yellow (X), pale greenish-yellow (Y), greenish-yellow (Z) |
| 2V: | 72o (measured) |
| Fluorescence: | Greenish-white |
| Other: | Radioactive |
| References: | [2] |
Oppenheimerite is a very rare uranium mineral with the formula Na2(UO2)(SO4)2•3H2O.[3] Chemically related minerals include fermiite, natrozippeite, plášilite, belakovskiite and meisserite.[4] [5] [6] [7] [8] Most of these uranyl sulfate minerals were originally found in the Blue Lizard mine, San Juan County, Utah, US.[9] The mineral is named after American Theoretical physicist J. Robert Oppenheimer.
Oppenheimerite is associated with other sulfate minerals: fermiite, bluelizardite, wetherillite, blödite, chalcanthite, epsomite, gypsum, hexahydrite, kröhnkite, manganoblödite, sideronatrite, and tamarugite.
The crystal structure of oppenheimerite is of a new type. It contains chains of the (UO2)(SO4)2(H2O) composition, connected with two types of sodium polyhedra.