Darwin Glass is found only in Tasmania. This rare and beautiful material was formed 816,000 years ago when a meteorite slammed into Western Tasmania near what is now known as Mount Darwin. The meteorite, somewhere between twenty and fifty metres in diameter, impacted with the force of a twenty megaton nuclear weapon.
Utube video https://www.youtube.com/watch?v=0g4uIg78xUY
The explosion melted the local rock and the meteorite into liquid form and scattered it over a surrounding area of at least four hundred square kilometres. The liquid cooled rapidly in flight, forming twisted, rope-like curls, and rarer splash form types including teardrops, spheres, disks, and dumbells.
Within some pieces, air bubbles are easily observable, preserving samples of the Earth’s atmosphere from almost a million years ago.
Darwin Glass is found as light green-white or dark-green-brown specimens. The darker glass contains, relative to the lighter glass, less silica and more magnesium, iron, chromium, nickel and cobalt. It is thought these differences are due to the differing levels of extraterrestrial material from the original meteorite.