Quartz diorite is an igneous, plutonic (intrusive) rock, of felsic composition, with phaneritic texture.
Biotite, amphiboles and pyroxenes are common dark accessory minerals.
[1] Quartz diorite occurs in association with other granitic rock such as granodiorite, and with volcanic rock.
In western North America a "quartz diorite line" occurs; west of this line, the dominant granitic rock is quartz diorite.
This igneous rock-related article is a stub.