Yellow green crystals of the very rare new uranium mineral shumwayite (IMA 2015-058) on a contrasting black matrix from the type locality in Utah (Giveway-Simplot Mine, Red Canyon, San Juan County, Utah, United States of America). — Photo: David Hospital · CC BY-SA 4.0
Shumwayite
A simple hydrated uranyl sulfate from Utah's Green Lizard mine — a rare uranium secondary.
Intro adapted from Wikipedia (CC BY-SA).
Shumwayite is an IMA-recognized mineral species in the sulfate class, with the chemical formula [(UO₂)(SO₄)(H₂O)₂]₂·H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: Mohs hardness 2; specific gravity 3.844; White streak; Vitreous luster; optically biaxial.
IMA symbol Smw, IMA status: approved, named in 2015.
Found in efflorescent crusts formed by hydration-oxidation weathering of primary uranium minerals (esp. uraninite) by acidic solutions derived from the decomposition of associated sulfides.
It is found associated with Calcite, gypsum, plášilite, pyrite, rozenite, sulfur (Green Lizard mine); asphaltum, rietveldite, rhomboclase, römerite (Giveaway-Simplot mine).
The mineral was named to honor the Shumway family. Family members account for the discovery and mining of hundreds of uranium deposits on the Colorado Plateau, USA. Arah E.