Sid″er‐ite, n. [L. sideritis loadstone, Gr. ����, ����, of iron, from ���� iron.] 1. (Min.) (a) 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. (b) A meteorite consisting solely of metallic iron. (c) An indigo-blue variety of quartz. (d) Formerly, magnetic iron ore, or loadstone.
2. (Bot.) Any plant of the genus Sideritis; ironwort.