28.5 million years ago, a meteorite hit the Libyan desert, the extreme temperature of which melted the sand and created the purest natural quartz glass on Earth.
Libyan glass is yellow to greenish in color, often containing brown inclusions - remnants of the original meteorite. Unlike tektites, it was formed directly at the impact site.
It was already used in ancient Egypt, including on the necklace of Pharaoh Tutankhamun.