Ferruginous
Ferruginous (fer*ru"ji*nus) , adjective
[Latin ferruginus, ferrugineus, from ferrugo, -ginis, iron rust: compare French ferrugineux. See Ferrugo.]
1.
Partaking of iron; containing particles of iron. — Boyle
2.
Resembling iron rust in appearance or color; brownish red, or yellowish red.