Learn about these strange glass blobs that showered the Earth millions of years ago.
Tektites are pebble-sized, often intricately shaped glass objects. They are much like obsidian glass, which is formed by terrestrial volcanic eruptions, except tektites have a far higher melting point and a thousand times less water content. Tektites are mainly composed of silica and contain bands of lechatelierite silica glass, which is formed naturally when lightning strikes quartz sand. Under the microscope, they display very little or no crystal structure.
The dominant theory is that they were created by meteorite/asteroid impacts several million years ago. The incredible heat and pressure generated by a huge space rock smashing into Earth would melt rocky layers and blast rubble at high velocity into the atmosphere. This would rain down over the impact site, to a distance of 6,000 kilometres (3,730 miles), as tektites. As they fell to the ground, they morphed into various shapes, like discs, dumbbells, spheres, rods and teardrops.
This theory is supported by the fact that strewn fields of tektites surrounding one impact area are distinct from the type of tektites found surrounding another impact site.