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SC176 - Bayleyite

Locality: Hideout Mine, Deer Flat, White Canyon, White Canyon District, San Juan Co., Utah, USA (MINDAT)
Size: 5 x 3 x 1 cm - Miniature (3-6 cm)
Weight: 4 g
minID: 7J2-KFP

Bright green fluorescent under all wavelengths. Under short wave UV it is has a uniform green/blue color, while under long wave and 405nm laser there is a green/bluish background and some more yellowish “flowers”. I’m not sure which is the bayleyite, probably it is a mixture of secondary uranium minerals.

Almost all of the fluorescent material from the Hideout #1 comes from the first 30 meters inside the portal. Rainwater and snow melt entering the mine adit allowed several Uranium secondaries to form evaporites on the walls of the adit.

Many of the samples from this mine show a pale yellow mineral and a white material, both evaporites. The pale yellow (visible light) is bayleyite, as some specimens show the radiating needle-like crystal structure. Many specimens however, have been subjected to repeated bouts of solution and deposit, and have a lumpy, non crystalline appearance. At least some of the white material is calcium carbonate, which has formed a layer on top of the bayleyite. Some of the material could be rabbitite.

The fluorescence spectrum shows typical UO2 ions profile. Very similar spectra are obtained under short wave, long wave, and 405nm laser.

It is not too much radioactive: I measure 0.36 uS/h of beta+gamma, just 3 times the background here (but it is very powdery and water soluble (?), so beware!)

Photo in normal light.
Fluorescence under shortwave UV light (254nm Hg light).
Fluorescence under longwave UV light (365nm LED).
Fluorescence under 405nm blue laser, with yellow filter.
Last update: 01 January 2021