small, glassy objects that result from an ancient asteroid impact; can be dated by potassium-argon and fission-track dating methods

any of various rounded, glassy objects of different shapes and weights, found in various parts of different parts of the world and thought to have come from the moon or to have resulted from the impacts of large meteorites on terrestrial rocks. [AHDOS

Tektites (from Greek tektos, molten) are natural glass objects, up to a few centimeters in size, which — according to most scientists — have been formed by the impact of large meteorites on Earth's surface. Tektites are among the "driest" rocks, with an average water content of 0.005%. This is very unusual, as most if not all of the craters where tektites may have formed were underwater before impact.