This rock is predominantly formed of amphibole, commonly hornblende, but sometimes actin olite or tremolite. Feldspar, pyroxene, chlorite, epidote, and garnet are also often present.

TEXTURE This is a coarse-grained rock. A well-developed foliation or schistosity can occur, and there may be porphyroblasts, particularly of garnet.

ORIGIN Medium- to high-grade rocks, amphibolites are formed mostly from the metamorphism of igneous rocks such as dolerites.

Group: METAMORPHIC

Grain size: Coarse

Classification: Regional

Pressure: High

Temperature: High

Structure: Foliated, Crystalline