Answer: plumbago

AnswerCrossword Clue
PLUMBAGOGraphite
PLUMBAGOBlack lead.
PLUMBAGOLead plant
plumbagovery common mineral, soft native carbon, occurring in black to dark-gray foliated masses, with metallic luster and greasy feel: used for pencil leads, as a lubricant, and for making crucibles and other refractories; plumbago; black lead
plumbagodrawing made by an instrument with a lead point
plumbagographite (a soft variety of carbon)