1. (n.) Carbonate of iron, an important ore of iron occurring 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.