A

David

Darling

spilite

spilite

Spilite is a fine-grained, extrusive igenous rock found near volcanoes. The dark-colored rock occurs as pillow lava, which is formed where lava from a volcanic eruption flows into the sea; it often contains cavities formed by gas bubbles. It is a basic rock containing up to 40% silica and more sodium than basalt, the common volcanic rock.