a hard, very heavy, dark-colored, radioactive mineral, UO, the chief ore of uranium; uranium oxide
Origin:
< uranium + -in + -ite
See uraninite in American Heritage Dictionary 4
noun
A complex brownish-black mineral, UO2, forming the chief ore of uranium and containing variable amounts of radium, lead, thorium, and other elements. It is isomorphous with thorianite.
Origin:
Origin: German Uranin (from New Latin ūranium, uranium; see uranium)