Definition of obsidian in English:


Pronunciation /əbˈsidēən/ /əbˈsɪdiən/ /äbˈsidēən/ /ɑbˈsɪdiən/


  • 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.’
    • ‘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.’


Mid 17th century from Latin obsidianus, error for obsianus, from Obsius, the name (in Pliny) of the discoverer of a similar stone.