Australites are small, button- or lens-shaped pieces of glass found in the southern part of Australia. Their chemical composition and low water content distinguishes them from volcanic glass (see Obsidian). Early miners called them button stones, blackfellows’ buttons, or emu stones. Most such glass pieces are about 1 inch (2.54 centimeters) in diameter and are black or dark green. They are rich in the mineral silica, or silicon dioxide. Similar glasses are found in other parts of the world, notably in southeast Asia, Libya, and the southeastern United States. Scientists call these glasses tektites. They believe the stones were formed by the impact of meteorites and shaped by rapid flight through the atmosphere. See Tektite.
