Natural earth used as a yellow or red pigment (5)
I believe the answer is:
ochre
(Other definitions for ochre that I've seen before include "Mineral pigment; chore (anag.)" , "Yellow-red earthy pigment" , "Yellowish-brown or red pigment" , "Earthy pigment - light brownish-yellow" , "Pigment made from clay and iron oxide" .)