Several pieces of bornite.
bornite 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 reddish-brown, soft, brittle, cubic mineral, copper iron sulfide, CuFeS, an ore of copper that tarnishes to a dark purplish color when it is fractured
Origin: after Ignaz von Born (1742-91), Austrian metallurgist
bornite definition by American Heritage Dictionary
A brownish-bronze, lustrous copper ore with the composition Cu5FeS4 that tarnishes to purple when exposed to air.
Origin: After Ignaz von Born (1742-1791), Austrian mineralogist.