Australite

[1] Indigenous Australians from the Diyari group termed australites ooga ("staring eyes"), and they were used as sacred objects or as cutting tools.

[2] Europeans found out about australites in 1857, when explorer Thomas Mitchell gave naturalist Charles Darwin a mysteriously shaped piece of natural black glass.

[4] Early theories about the source of australites included volcanoes, the bushfires that are common in Australia, or fusion of sand by lightning (fulgurites).

The australites acquired their streamlined, aerodynamic forms when they re-entered the Earth's atmosphere while molten and travelling at high velocities.

Flanged buttons are rare, but the most unusual and rarest australites are discs, bowls, plates and other small forms (mini tektites).

George Baker called them "flying flanges", the result of distortion of "initially small primary forms by aerodynamic frictional heating".