Red Ochre

From BiblePortal Wikipedia

Red Ochre [1]

ō´kẽr , (  Isaiah 44:13 , "He marketh it out with a pencil," margin "red ochre," the King James Version "line"; שׂרד , seredh , a word found only here, and of unknown etymology): Designates the implement used by the carpenter to mark the wood after measuring and before cutting. "Red ochre" supposes this to have been a crayon (as does "pencil"), but a scratch-awl is quite as likely. Ochre is clay colored by an iron compound.