Tektite comes from Greek tektos, meaning molten. Tektites are natural glass objects that scientists believe are formed by the impact of large meteorites. They are typically black or olive green with shapes varying from round to irregular.

Tektites are some of the “driest” rocks, with an average water content of 0.005%. This is highly unusual, because most if not all of the craters where tektites may have formed were underwater before impact. Partially melted zircons have sometimes been discovered inside tektites. This, along with the water content, suggests that the tektites were formed under temperatures and pressures not normally found on the surface of the Earth.

The impact theory states that a meteorite impact melts material from the Earth’s surface and catapults it up to several hundred kilometers away from the impact site. The molten material cools and solidifies to glass. as determined from isotopic measurements, a meteorite impact causes their formation, but the precursor material of tektites is primarily of terrestrial origin. Today, the terrestrial origin of tektites is widely accepted based on the results of many geochemical and isotopic studies (e.g. Faul H.(1966), Koeberl C.(1990)).

The theory also relies on the observation that tektites cannot be found everywhere on Earth’s surface. They are only found in four strewnfields associated with known impact craters. Only the largest and geologically youngest tektite deposit in Southeast Asia, called the Australasian strewnfield, has not been definitively linked to an impact site, probably because even very large impact structures are often not easy to detect. For example, one of the largest known impact sites in the U.S. the Chesapeake Bay impact crater, was not detected until the early 1990s since it is covered by sediments. The bigger the strewnfield, the bigger the area to search for the crater. Since several new craters are identified every year, this is not really regarded as a problem by proponents of the tektite impact theory, except for the expected Australasian crater, a feature that would be less than a million years old and thus easily visible. This crater, if it exists at all, has not been located.

Moldavites are a type of tektite found in Czech Republic.

Tektites are sometimes called by other names, depending on the part of the world and their characteristics. Below are some types of Tektites.

European strewnfield -Nördlinger Ries, Germany

Moldavites -Czech Republic, green

Australasian strewnfield -no associated crater identified; but see Wilkes Land crater

Australites -Australia, dark, mostly black

Indochinites -South East Asia, dark, mostly black

Chinites -China, black

North American strewnfield -Chesapeake Bay impact crater, USA

Bediasites -USA, Texas, black

Georgiaites -USA, Georgia, green

Ivory Coast strewnfield -Lake Bosumtwi Crater, Ghana

Ivorites -Ivory Coast, black