[uh b-sid-ee-uh n]


a volcanic glass similar in composition to granite, usually dark but transparent in thin pieces, and having a good conchoidal fracture.

Origin of obsidian

1350–1400; < Latin Obsidiānus, printer's error for Obsiānus pertaining to Obsius, the discoverer (according to Pliny) of a similar mineral in Ethiopia; replacing Middle English obsianus < Latin; see -an
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for obsidian

Contemporary Examples of obsidian

Historical Examples of obsidian

  • Agates, cornelians, obsidian, are also among the products of this nature.


    Charles Reginald Enock

  • “Looks like black glass, sir,” said Ned, kicking a piece of obsidian.

    Jack at Sea

    George Manville Fenn

  • I was to do the heating of the obsidian and Pitamakan was to do the flaking.

    With the Indians in the Rockies

    James Willard Schultz

  • Their weapons were slings, spears, and arrows with points made of obsidian or bone.


    Susan Hale

  • But many of them are of obsidian, some of which are beautifully clear.

    A Journal from Japan

    Marie Carmichael Stopes

British Dictionary definitions for obsidian



a dark volcanic glass formed by very rapid solidification of lavaAlso called: Iceland agate

Word Origin for obsidian

C17: from Latin obsidiānus, erroneous transcription of obsiānus (lapis) (stone of) Obsius, the name (in Pliny) of the discoverer of a stone resembling obsidian
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

Word Origin and History for obsidian

"dark, hard volcanic rock," 1650s, from Latin obsidianus, misprint of Obsianus (lapis) "(stone) of Obsius," name of a Roman alleged by Pliny to have found this rock in Ethiopia.

Online Etymology Dictionary, © 2010 Douglas Harper

obsidian in Science



A shiny, usually black, volcanic glass. Obsidian forms above ground from lava that is similar in composition to the magma from which granite forms underground, but cools so quickly that minerals do not have a chance to form within it.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.