noun

• A hard, dark, glasslike volcanic rock formed by the rapid solidification of lava without crystallization.

  ‘Hard stones such as obsidian and rock crystal were added to the repertoire of the stone-vase maker.’

  More example sentences

  • ‘The earliest mirrors were of obsidian, a black volcanic rock that could be carved and polished.’
  • ‘The presence of basalt and obsidian is a sign of volcanic activity and the instability of the earth's crust in this area.’
  • ‘Silent as stones like two black pillars carved from obsidian rock.’
  • ‘Obsidian looks like coal and while both are black, obsidian is shinier.’