Zippeite Locality: Delta Mine (Hidden Splendor), San Rafael District (San Rafael Swell), Emery County , Utah , USA ( Locality at mindat.org ) Size: 6.4 x 5.1 x 4.5 cm. The yellow patches you see here are probably zippeite (darker yellow) and uraninite (uranium oxide- lighter yellow) - this specimen came from the Delta Mine in Utah, which was mined almost exclusively for uranium; this specimen went to the well-known collection of the School of Mines in Paris. The label has the significant mineral misidentified (or the name changed over 100 years of specimen terminology changes, rather), though it does mention "one new sulfate or yellow uranium?" which we presume to be the zippeite (potassium uranium sulfate) although have not analyzed to confirm 100%. Yes, it is basically yellow uranium species, probably several, and is an interesting historic piece. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Zippeite
A yellow-to-orange hydrated potassium uranyl sulfate — fluorescent crusts on uranium-mine walls.
Intro adapted from Wikipedia (CC BY-SA).
Zippeite is an IMA-recognized mineral species in the sulfate class, with the chemical formula K₂[(UO₂)₄(SO₄)₂O₂(OH)₂](H₂O)₄.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Zippeite structural group.
Key properties: Mohs hardness 2; specific gravity 4.8; Vitreous luster; optically biaxial.
IMA symbol Zip, IMA status: approved, named in 1845.
An uncommon secondary mineral, in part post-mine, in oxidized uranium deposits.
It is found associated with Uranopilite, natrozippeite, nickelzippeite, magnesiozippeite, johannite, uranophane, schröckingerite, gypsum.
The mineral was named to honor Dr. František Xaver Maximillian Zippe (1791-1863), Austrian mineralogist and geologist.