East Pacific Rise pillow basalt main content.

East Pacific Rise pillow basalt

Part of Hall of Planet Earth.

East Pacific Rise Pillow Basalt AMNH/R.Mickens

The reddish rind on this pillow is made of palagonite, a clay-rich layer that formed when pillow’s hot exterior reacted with cold seawater.  The black manganese minerals on the surface build up over time, indicating that this pillow is older than others displayed here.

Loaned by the Scripps Institute of Oceanography