Tektites are pieces of glass formed when a large meteorite strikes the Earth. Tektites and associated impact melted rock are found in only a few regions on Earth (called tektite strewn fields) and are, in most cases, associated with young impact craters on or near land. Tektite looks similar to obsidian glass but can be differentiated by color and chemical composition. Pictured here is a "splash form tektite".