Simplify the following text for a Grade 12 native English-speaking person.
Original: Very dark brown to black hornblendes that contain titanium are ordinarily called basaltic hornblende , from the fact that they are usually a constituent of basalt and related rocks .
Simplified: 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 .