Libyan Desert Glass: How Did Impact Glass Reach Tutankhamun?
Yellow glass scattered in the Sahara, formed by a cosmic event 29 million years ago, carved into the scarab on Tutankhamun's pectoral.
Libyan desert glass is almost pure silica glass scattered in Egypt's Great Sand Sea, formed about 29 million years ago by a cosmic impact or airburst. The scarab on a Tutankhamun pectoral is carved from it.
In the Great Sand Sea of western Egypt, near the Libyan border, lie pieces of pale yellow-green glass, some as big as a fist or larger, spread over a wide area of desert. They are almost pure silica, about 98 percent, and formed about 29 million years ago when sand was melted at temperatures far higher than any volcano or wildfire can reach. Patrick Clayton's desert survey brought the field to scientific attention in 1932.
People knew the glass long before that. Stone Age toolmakers knapped it into blades. And among the treasures of Tutankhamun, who died around 1323 BCE, is a pectoral whose central winged scarab is carved from a translucent yellow stone. In 1998 the Italian mineralogist Vincenzo de Michele identified it as Libyan desert glass.
How the glass formed has long been debated. One idea is an airburst, a meteor exploding in the atmosphere and melting the sand below with radiant heat. The other is a direct impact. In 2019 Aaron Cavosie and Christian Koeberl reported zircon grains in the glass showing traces of reidite, a mineral that forms only under the extreme pressure of an impact, which pointed toward a meteorite strike, though no crater has been confirmed.
The story links a king's jewelry to a cosmic event. It invites speculation, but the science is clear on one point: this was a natural event, millions of years before any human saw the sky. Researchers continue to search for the source crater, and the glass remains a favorite example for scientists studying how cosmic impacts melt rock and sand. That a piece of it ended up at the heart of a pharaoh's jewelry, chosen for its color, is a coincidence that has fascinated people ever since.
The scarab at the center of Tutankhamun's jewelry is made of glass created by a meteorite event about 29 million years before the pharaoh lived.
Geologists agree the glass is natural and formed by an impact or airburst tens of millions of years ago; it has no connection to ancient human technology.
