Geocentric Science

Obsidian is a Felsic to intermediate, extrusive igneous rock, which forms when silica-rich magma flows onto the Earth’s surface and solidifies extremely rapidly before minerals can develop and crystallize. It is classified as an amorphous solid or glass.

Obsidian often appears dark green to black in color due to minerals containing magnesium and iron as well as its non-crystalline structure. Other variations of obsidian include snow-flake obsidian and rainbow obsidian.