Tektites are an unusual formation. The name comes from the Greek "tektos" meaning melted. Tektites are believed to have formed by the impact of large meteors on the Earth's surface. These impacts would shoot sand, rock, and other debris high up into the atmosphere. When this debris fell from the sky and came back to the surface, it was superheated and changed during re-entry, becoming a tektite.
Tektites
Tektites