Lead 10000 to 9318 -- 8548 Tin ---- to 9107 -- 8679 Clay ---- to 7938 -- 7643 Porcelain ---- to 7692 -- 8863 Oker ---- to 6289 -- 6500 Chalk ---- to 6104 -- 6195 Gypsum ---- to 4160 -- 6011 Wood ---- to 2647 -- 5514