These cliffs proved, as Bennie had already suspected, to be a gigantic outcrop of pitchblende or black oxide of uranium.
"The Man Who Rocked the Earth"
Arthur Train Robert Williams Wood
The deposits of Joachimsthal, Bohemia, contain pitchblende, along with silver, nickel, and cobalt minerals and other metallic sulphides, in veins associated with igneous intrusions.
"The Economic Aspect of Geology"
C. K. Leith
The principal ore mineral is uranophane, a hydrated calcium-uranium silicate, which is believed to be an oxidation product of pitchblende.
"The Economic Aspect of Geology"
C. K. Leith