(1):

(n.) Carbonate of iron, an important ore of iron occuring generally in cleavable masses, but also in rhombohedral crystals. It is of a light yellowish brown color. Called also sparry iron, spathic iron.

(2):

(n.) A meteorite consisting solely of metallic iron.

(3):

(n.) An indigo-blue variety of quartz.

(4):

(n.) Formerly, magnetic iron ore, or loadstone.

(5):

(n.) Any plant of the genus Sideritis; ironwort.