Oppenheimerite
A very rare hydrated sodium-uranyl sulfate, related to fermiite and meisserite.
Intro adapted from Wikipedia (CC BY-SA).
Oppenheimerite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Na₂(UO₂)(SO₄)₂·3H₂O.
It crystallizes in the triclinic crystal system (space group P-1).
Key properties: Mohs hardness 2.5; specific gravity 3.36; White streak; Vitreous luster; optically biaxial.
IMA symbol Ohm, IMA status: approved, named in 2014.
A secondary mineral from post-mining oxidation of primary uraninite, pyrite, chalcopyrite, bornite, and covellite deposited as replacement of wood and other organic material and as disseminations in the enclosing sandstone.
It is found associated with Fermiite, blödite, bluelizardite, chalcanthite, epsomite, gypsum, hexahydrite, kröhnkite, manganoblödite, sideronatrite, tamarugite, wetherillite.
The mineral was named to honor American physicist Dr. J. Robert Oppenheimer (1904-1967), former Professor of Physics concurrently at the University of California.