Tektites (from Greek τηκτός tēktós, "molten") are gravel-sized bodies of natural glass. They come in green or brown (usually). They are formed from terrestrial debris ejected during meteorite impacts. The term was coined by Austrian geologist Franz Eduard Suess (1867–1941). They generally range in size from millimeters to centimeters. Millimeter-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 (silica glass, amorphous SiO2)
- a general lack of microscopic crystals known as microlites and chemical relation to the local bedrock or local sediments
- their distribution in widespread strewn fields