Answer: foolsgold

AnswerCrossword Clue
FOOLSGOLDForty-niner's offensive material?
FOOLSGOLDForty-niner's disappointment
FOOLSGOLDFeS2, commonly
FOOLSGOLDProspector's letdown
FOOLSGOLDIron pyrite
FOOLSGOLDForty-niner's disillusionment
FOOLSGOLDIron pyrites, a hoax for miners.
FOOLSGOLDDeceptive ore.
FOOLSGOLDIron or copper pyrites.
FOOLSGOLDIron pyrites.
FOOLSGOLDPyrite
FOOLSGOLDIron sulfide with a deceiving color