Classification of Metamorphic Rocks (Part 5)
Dark and red-brown crystals of garnet in schist indicate medium-grade metamorphism. Garnet is an aluminum-rich silicate mineral.
Schist (Photograph by Parvinder Sethi)
Elongated brown crystals of staurolite in schist indicate medium- to high-grade metamorphism. Staurolite is commonly known as fairy stone. Staurolite contains iron, magnesium, aluminum, and silicate.
Staurolite (Photograph by Parvinder Sethi)
Bladed blue crystals of kyanite in schist indicate high-grade metamorphism. Kyanite is made up of aluminum and silicate.
Kyanite (Photograph by Parvinder Sethi)