Delta Mine (Hidden Splendor), San Rafael District (San Rafael Swell), Emery Co., Utah, USA
Small Cabinet, 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.