Pacific Ocean pillow basalt main content.

Pacific Ocean pillow basalt

Part of Hall of Planet Earth.

Pacific Ocean Pillow Basalt AMNH/R.Mickens

The glassy crust has broken off the rounded surface of this pillow, exposing the dark, fine-grained basalt beneath. The radial pattern of fractures on the side is typical of pillows that cool quickly from their outer surface ot their center, quenched by cold seawater.

Loaned by the Geological Survey of Japan