- Nuclear fuel - Radioactive element - Yellowcake product - An element of the chromium group, found in certain rare
minerals, as pitchblende, uranite, etc., and reduced as a heavy, hard,
nickel-white metal which is quite permanent. Its yellow oxide is used
to impart to glass a delicate greenish-yellow tint which is accompanied
by a strong fluorescence, and its black oxide is used as a pigment in
porcelain painting. Symbol U. Atomic weight 239.