Tektites

Tektites (other-Greek. τηκτός - —molten" or "melted") — a class of impactite rocks, which are small melted pieces of light green, dark green, sometimes black, whitish or yellow glass of various shapes, most often with characteristic inclusions in the form of gas bubbles. They are of meteoritic, asteroid or cometary origin.

In appearance and properties, tektites slightly resemble obsidian, but differ from it in chemical composition. Some resemble small dumbbells or plates, others look like pears, bulbs, fingers, buttons, hollow spheres, boats, tears, hollow thin-walled balls, cores, disks, plates, coins, beans and trilobites. Individual samples have a complex sculpture, as if their surface has been eaten away.

A layman may well confuse them with fragments of ordinary bottle glass.

At the beginning of the XX century, these strange formations were called tektites (from other Greek. τηκτός, which means "melted"). Their sizes vary — from tiny glass beads to pieces comparable in size to a chicken egg and weighing almost half a kilogram or more.

Finds of tektites are known on all continents, including Antarctica.