Hornblende \Horn"blende`\, n. [G., fr. horn horn + blende blende.] (Min.) The common black, or dark green or brown, variety of amphibole. (See {Amphibole}.) It belongs to the aluminous division of the species, and is also characterized by its containing considerable iron. Also used as a general term to include the whole species. {Hornblende schist} (Geol.), a hornblende rock of schistose structure.