From Longman Dictionary of Contemporary Englishpitchblendepitch‧blende /ˈpɪtʃblend/ noun [uncountable] HEa dark shiny substance dug from the earth, from which uranium and radium are obtained
Examples from the Corpus
pitchblende• The cliff contains pitchblende veins that have been sources of dissolved uranium.• Veins of pitchblende in the cliff are the source of uranium in the flat floodplain deposits at the foot of the cliff. 