Libyan Desert Glass

http://commons.wikimedia.org/wiki/File:Libyan_Desert_Glass.jpg
Image: Wikimedia Commons

What is this stuff? Fragments of it can be found over large areas in the northeastern Sahara. No one’s sure where it came from — it could have arrived as part of a meteor, it could have been fused together in some ancient impact or under the heat of an aerial explosion. The jury’s still out.