noun

• A white solid that is a major constituent of many rocks, especially clays, and is found crystallized as corundum, sapphire, and other minerals.

  Alternative name: aluminium oxide; chemical formula: Al₂O₃

  ‘The silica, alumina, and iron come from sand, clay, and iron ore.’

  More example sentences

  • ‘The major exports are bauxite, alumina, gold, and diamonds.’
  • ‘Already some sites yield little more than a mass of crystallised aluminium oxide.’
  • ‘He derived the name from the mineral called alumina, which itself had only been named in English by the chemist Joseph Black in 1790.’
  • ‘The metals are dispersed as tiny particles on a supporting framework of porous aluminium oxide.’