At five widely separated locations on the Earth can be found rare and fascinating natural glass. Named tektite glass it is formed when asteroids strike the Earth. Not everything about how the glass forms is fully understood adding to the charm and mystery of this rare material.
 
The largest and youngest of the tektite strewnfields is that of Indochina. Covering a vast area from Australia to China, and including the Islands of the East Pacific these dark black tektites come in all sizes and shapes. The rocks which are melted and vaporized in the impact travel out to near space where the material cools to glass. As it is falling back to Earth the globs are still plastic. They are shaped by the atmosphere and by their spin into aerodynamic forms. Sphere, rods, dumbbells, patties, teardrops are among some of the shapes the glass receives. In addition to the glass which falls and becomes the splashforms just described is another type which seems to form near the impact site does not travel far. Instead it appears to pool and run on the ground. This tektite glass is layered and much more bubbly than that which falls from the sky. It is called Muong Nong Layered Tektite Glass after the region where it was first identified.

Tektite glass being made of the rock material which was targeted by the asteroid naturally has characteristics of that material. So some differences in color and texture are seen in the various locations where they are found. The other four strewnfields of tektite glass are Texas where the black Bediasites are found, Georgia where the beautiful yellow-green Georgiaites are recovered, the Ivory Coast of Africa where the appropriately named Ivory Coast tektites are found and one small strewnfield in Europe which deserves its own description. In  the Czech Republic are two areas where Moldavite tektite glass is found. The locations are Moravia, and Bohemia. The Moravian type are far more famous since they are the wonderful vibrant green. They are often beautifully etched and sculptured when found. Used for hundreds of years in jewelry these are prized still today for their color and form. The Bohemian Moldavites are usually brown in color and much rarer than their Moravian cousins. That scarcity makes them objects sought after by tektite collectors whenever they are available.

Whether they are Philippinites, Billitonites, Javanites, or mainland Indochinites from Thailand, Vietnam, Laos, or China, whether they are from the United States, Africa or Europe, tektites are the unique evidence of what happens sometimes when asteroids hit the Earth. Hundreds of impacts recorded, but only five tektite locations. What allows them to form only once in a great while is one of the important questions yet to be fully answered. Tektites remain mysterious objects formed by cosmic forces.