A mineral consisting chiefly of uranium oxide with some lead, thorium, etc., occurring in black octahedrons, also in masses with a pitchlike luster; pitchblende.

A uranium mineral with a high uranium oxide content. Frequently found in pegmatite dykes.

a mineral consisting of uranium oxide and trace amounts of radium and thorium and polonium and lead and helium; uraninite in massive form is called pitchblende which is the chief uranium ore