Mineralpedia Details for Boltwoodite
Named in honor of Bertram Borden Boltwood, a radiochemist formerly of Yale University in Connecticut, USA who developed the U-Pb method of measuring geologic time. Boltwoodite is a rare mineral that can be found “in the outer silicate zone of alteration surrounding hydrated uranyl oxides incrusting primary uraninite. [and] also filling fractures at some distance from primary uraninite, [as well as] from pegmatite and Colorado-Plateau-type sandstone uranium deposits.” Localities include in the USA, Namibia, Scotland, Rwanda, Argentina, Australia, Japan, and a few others. Boltwoodite is highly radioactive and will fluoresce dull green in short- and long-wave ultraviolet light.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/boltwoodite.pdf
Boltwoodite from Rossing mine, Rossing, Swakopmund, Namibia
Slender, radial, prismatic, yellow crystals of Boltwoodite.
Boltwoodite from Repete mine, San Juan Co., Utah, United States
Yellow powdery crust on mudstone matrix.