pitchblende

Pitchblende is the historical name for a uranium-rich ore, most often referring to the mineral uraninite. It consists mainly of uranium dioxide (UO2) and occurs with variable amounts of thorium and other elements; natural samples can deviate from pure UO2. The term derives from the German Pechblende, meaning tar-like ore, a reference to its black, pitchy appearance. Pitchblende is highly radioactive due to its uranium content and is often accompanied by decay products such as radium and thorium.

Geologic occurrence and deposits: Pitchblende forms in a variety of settings, including hydrothermal veins, granitic pegmatites, and sedimentary uranium deposits. Historically, major sources came from Joachimsthal (Jáchymov) in Bohemia and other ore-bearing regions in the Ore Mountains.

Economic and historical significance: Pitchblende has long been the principal ore of uranium. Processing the ore yields uranium for use as fuel and, in the late 19th and early 20th centuries, provided residues from which radium and polonium were later isolated by the Curies.

Terminology and current usage: In modern mineralogy, the formal mineral name for the uranium oxide is uraninite; pitchblende remains a historical term for uranium-rich ore. The chemistry of pitchblende can include thorium and trace amounts of other radioactive elements, which influence handling and processing.

Safety: The radioactivity of pitchblende requires careful handling, ventilation, and protective measures to limit radiation exposure.