Deep-ocean pillow basalt
This sample was dredged from a seafloor spreading center near Japan. The shiny black surface is glass, a product of rapid cooling of lava underwater. The white crystals in the glassy crust are plagioclase, a common mineral in most rocks.
Loaned by the Geological Survey of Japan
Topic: Earth Science
Keywords: Basalt, Japan, Mid-ocean ridges, Ocean bottom, Plagioclase, Volcanoes