Tektite
A piece of natural glass made when a large impact melted rocks on Earth and threw the molten droplets far away.
A tektite is a small piece of black, brown or green glass, usually a few centimetres across. Tektites are not meteorites. They are made of Earth rock that was melted by a huge impact and splashed high above the ground, where it cooled into droplets before falling back hundreds or even thousands of kilometres away. Their shapes record that flight: spheres, teardrops, dumbbells, discs and buttons, often with pitted, grooved surfaces.
Tektites fall over vast areas called strewn fields, and each one comes from a single impact. The Australasian field, about 790,000 years old, stretches from South-East Asia to Australia and is the largest; its crater has not yet been confirmed. Green moldavites, found mostly in the Czech Republic, came from the Ries impact in Germany nearly 15 million years ago. Other fields lie in Ivory Coast, linked to the Bosumtwi crater in Ghana, and in North America, linked to the buried Chesapeake Bay crater.
To recognise a tektite, look for glassy material with shell-like fracture, a splash shape and an etched, sculpted surface. Unlike volcanic obsidian, tektites contain almost no water and very few crystals. Many glass and slag fakes are sold, so buy from reputable sources.
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Level: Explorer Ages 10 and up