Hornblende is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole.
Hornblende has a hardness of 5–6, a specific gravity of 2.9–3.4 and is typically an opaque green, greenish-brown, brown or black color. It is most often confused with the minerals augite and biotite mica, both of which are black and can be found in granite.
Occurrence[change | change source]
Very dark brown to black hornblendes that contain titanium may be called basaltic hornblende, from the fact that they are usually a constituent of basalt and related rocks.
Etymology[change | change source]
The word hornblende is derived from the German horn and blenden, to 'blind' or 'dazzle'. The term blende is often used to refer to a brilliant non-metallic luster, for example, zincblende and pitchblende, the ore of uranium.