When a bolt of lightning strikes loose sand, the electric charge vaporizes a thin wormhole and melts the zone around it, creating an instant froth of natural glass. These tubes—fulgurites—can be a meter long or more, but they're fragile, and what you see in rock shops is usually a piece like this, 4 centimeters long and as light as pumice. Sometimes a fulgurite forms in solid rock. This fulgurite specimen came from the Sahara Desert in Morocco.
Fulgurite is scientific Latin for "lightning stone."
Fulgurite is scientific Latin for "lightning stone."
