Metamorphic rock
Amphibolite
High-grade rock from mafic igneous rock such as basalt, made of amphibole (hornblende) and plagioclase with aligned crystals.
In thin section
Hornblende and plagioclase, with crystals aligned.
More photos and thin sections
Other metamorphic rocks
Slate · Phyllite · Schist · Gneiss · Marble · Quartzite · Hornfels · Migmatite
Sources
Panchuk, Physical Geology 10.3: Classification of Metamorphic Rocks