pitchstone definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a volcanic glass that somewhat resembles pitch and has a higher percentage of water than obsidian or other glassy rocks
Origin: calque of German pechstein ; from pech (; from Classical Latin pix), pitch plush stein, stone
pitchstone definition by American Heritage Dictionary
Any of various volcanic glasses distinguished by their dull pitchlike luster.
Origin: Translation of German Pechstein.