- a natural glass produced when molten lava cools very rapidly; obsidian.
Origin of volcanic glass
First recorded in 1830–40
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for volcanic glass
She armed herself with an obsidian or volcanic-glass knife, and waited their coming.
- any of several glassy volcanic igneous rocks, such as obsidian and pitchstone
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- Natural glass produced by the cooling of molten lava too quickly to permit crystallization. Obsidian is a type of volcanic glass.
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