Dictionary

obsidian

obsidian

noun ob·sid·i·an \əb-ˈsi-dē-ən\

: a dark natural glass that forms when lava cools

Full Definition of OBSIDIAN

:  a dark natural glass formed by the cooling of molten lava

Origin of OBSIDIAN

New Latin obsidianus, from Latin obsidianus lapis, false manuscript reading for obsianus lapis, literally, stone of Obsius, from Obsius, its supposed discoverer
First Known Use: 1796

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