57.0 "Greenstone" (metabasalt). Pillowed. Rock Point, Sonoma Coast State Park, California. The rock is aphanitc and green, hence the name “greenstone.” In this picture, rounded pillows are cut locally by shear planes and white calcite veins. [Pillows measure 10 cm to 30 cm. The thin gray layer at left is about 2 cm thick, for scale.]