Gabbro

The photographs above are crossed polarizer views of gabbros. The brightly colored minerals are clinopyroxene, and the white to gray minerals are plagioclase. The black minerals in both pictures are opaque grains of magnetite. Gabbros have more than 35% ferromagnesian minerals, and plagioclase composition in greater than An50. Gabbro is the intrusive equivalent of basalt.

The photographs below (crossed polarizers) shows a gabbro with brightly colored and fractured olivine surrounded by plagioclase (left photo) and a gabbro with cumulate texture, plagioclase poikilitically enclosed by clinopyroxene.