Outstanding yellow crystals of the rare uranium mineral ammoniozippeite associated to green johannite, from Blue Lizard Mine, Red Canyon, San Juan County, Utah, United States of America. — Photo: David Hospital · CC BY-SA 4.0
Ammoniozippeite
Ammoniozippeite is an IMA-recognized mineral species in the sulfate class, with the chemical formula (NH₄)₂[(UO₂)₂(SO₄)O₂]·H₂O.
It crystallizes in the orthorhombic crystal system (space group Ccmb). It is a member of the Zippeite structural group.
Key properties: Mohs hardness 2.5; Pale yellow streak; Vitreous luster; optically biaxial.
IMA symbol Azip, IMA status: approved, named in 2017.
A secondary mineral on the walls of mines in U-V deposits that replaced wood and other organic material in sandstones and conglomerate (roll-front type U-V deposits).
It is found associated with Blödite, bobcookite, brochantite, chalcanthite, devilline, dickite, ferrinatrite, gerhardtite, gypsum, johannite, krönkite, magnesiozippeite, natrozippeite.
As the ammonium analogue of zippeite, with (NH4)+ in place of K+.