Answer: anthracite

AnswerCrossword Clue
ANTHRACITEBlack diamonds
ANTHRACITEProduct of the Keystone State.
ANTHRACITEHard, lustrous coal
ANTHRACITEPetrified product of Pa.
ANTHRACITEMineral with high carbon content
ANTHRACITEStone coal
ANTHRACITEHard natural coal
anthracitea hard coal
anthracitehard coal