A plutonic rock consisting of plagioclase feldspar (labradorite), brown hornblende, minor augite, and biotite. The brown hornblende is thought to be of primary formation. A common accessory mineral is iron oxide (magnetite). Bojite is often visually striking, with patches and streaks and a layering of mafic minerals.

TEXTURE Coarse-grained, with crystals greater than 3⁄16 in (5 mm) in diameter. Grains are of the same size, but dark minerals tend to be in patches and layers.

ORIGIN Forms in plutonic environments at considerable depth in the Earth’s crust.

Group: IGNEOUS

Grain size: Coarse

Crystal shape: Anhedral, Euhedral

Classification: Mafic

Occurrence: Pluton

Color: Dark