• Glassy blobs found scattered on the Earth’s surface in distinct geographical regions and usually ranging in size up to a few centimetres across. Tektites seem to have been shaped aerodynamically by a passage while warm through the Earth’s atmosphere, but their origin is by no means certain meteorite impacts on the Moon are one postulated source although some process involving their being formed in the upper atmosphere from material ejected from the Earth by impact or from volcanoes is more favourably regarded by most scientists.