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[uh b-sid-ee-uh n] /əbˈsɪd i ən/
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 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for obsidian
Contemporary Examples
Historical Examples
  • Agates, cornelians, obsidian, are also among the products of this nature.

    Mexico 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
  • Her eyes, unveiled, black as obsidian, raised to meet Geo's.

    The Jewels of Aptor Samuel R. Delany
  • Scarabs of obsidian and crystal date back to the 4th dynasty.

  • We found among the ruins a few crude potsherds and some bits of obsidian.

    Inca Land Hiram Bingham
British Dictionary definitions for obsidian


a dark volcanic glass formed by very rapid solidification of lava Also called Iceland agate
Word Origin
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
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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
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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 © 2002. Published by Houghton Mifflin. All rights reserved.
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