Metamunirite, Zippeite, Andersonite xls; UV-active; D-Day Mine, Utah, USA; 1 flat

UV-active Metamunirite, Zippeite and Andersonite crystals from the D-Day Mine, Utah, USA, in 1 flat

This flat contains several specimens with Metamunirite, Zippeite and Andersonite from the D-Day Mine in Utah, USA. The pieces show mainly pale to grey matrix with whitish, cream-coloured to yellowish crystal areas, crusty coatings and fine-grained overgrowths. The individual specimens vary in appearance and show partly broad, partly more concentrated mineralized zones. Under UV light, several areas react clearly and display well visible green fluorescence. 

Geology & Origin

The D-Day Mine in Utah, USA, is a known locality for secondary uranium minerals. Metamunirite, Zippeite and Andersonite form there as weathering and oxidation products of primary uranium ores. These processes produce characteristic yellowish to whitish coatings, crusts and crystal aggregates on the host matrix. Andersonite is especially known for its distinct fluorescence under UV light, and the locality as a whole is appreciated by collectors for its diverse assemblages of fluorescent uranium minerals.