Fermiite
A rare sodium-uranyl sulfate related to oppenheimerite and meisserite, named for Enrico Fermi.
Intro adapted from Wikipedia (CC BY-SA).
Fermiite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Na₄(UO₂)(SO₄)₃·3H₂O.
It crystallizes in the orthorhombic crystal system (space group Pmn2_1).
Key properties: Mohs hardness 2.5; specific gravity 3.23; White streak; Vitreous luster; optically biaxial.
IMA symbol Fmi, 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 Oppenheimerite, blödite, bluelizardite, chalcanthite, epsomite, gypsum, hexahydrite, kröhnkite, manganoblödite, sideronatrite, tamarugite, wetherillite.
The mineral was named to honor Italian-American theoretical and experimental physicist Enrico Fermi (1901-1954), well known for his work for the Manhattan Project during World War II.