URA'NIUM, n. [Gr. heaven, or a planet so called.]

A metal discovered in 1789 by Klaproth, in the mineral called pechblend. It is occasionally found native in uran-ocher and uran-mica; but more generally it is obtained from pechblend, in which it exists with iron, copper, lead, and sometimes with arsenic, cobalt and zink.