Pitchblende

Pitchblende, radioactive mineral composed of the mineral uraninite, UO₂; it is one of the main ores of uranium. It is historically important as the mineral in which the chemical elements polonium and radium were first discovered in 1898 by the French scientists Pierre Curie and Marie Curie. Pitchblende was commercially important only as a source of radium until World War II, when it became extremely important as a source of uranium needed for the production of the atomic bomb.

Pitchblende is a black, opaque mineral with a dull, pitch-like lustre. The hardness is 5.5, and the relative density, which is extremely high for a mineral, ranges from 9.0 to 9.7. It crystallizes in the isometric system and usually occurs in massive formations as a constituent of granite rocks and pegmatites, or as a secondary mineral associated with silver, lead, or copper ores. Although the ores do not occur in large quantities throughout the world, the major sources of pitchblende are located in South Africa, the Czech Republic, United States, Canada, Germany, and France.