Tektites are gravel-sized bodies composed of black, green, brown or grey natural glass formed from terrestrial debris ejected during meteorite impacts. The term was coined by Austrian geologist Franz Eduard Suess, son of Eduard Suess. They generally range in size from millimetres to centimetres. Millimetre-scale tektites are known as microtektites.
Tektites are characterized by:
a fairly homogeneous composition
an extremely low content of water and other volatiles
an abundance of lechatelierite
a general lack of microscopic crystals known as microlites
not having a chemical relationship to the local bedrock or local sediments
their distribution within geographically extensive strewn fields
