Stīlp'no-sīd'er-īte, n.

(49) (Synop., § 130), n. [Gr. στιλπνός, shining, and σίδηρος, iron.] (Min.) A pitch-black or blackish-brown mineral, occurring in an amorphous, stalactitic, or massive state, and consisting chiefly of peroxide of iron and water. Dana.