Glass

To say that something hot happened in a desert doesn't sound all that remarkable. But what we're talking about was very hot—and the impact was extraordinary.

Roughly twenty-six million years ago, grains of silica in the sands of the Libyan Desert melted and fused under an intense heat that must have been at least 1,000 degrees Fahrenheit (538 degrees Celsius). Many scientists think a comet collision and explosion caused the event. When those superheated grains of sand cooled down below their melting point, a vast stretch of the Libyan Desert was coated with a layer of... glass .

About ten thousand years ago, give or take a few millennia, someone traveling through the desert stumbled across a large fragment of this glass. It circulated through the markets and social networks of early civilization, and ended up as the centerpiece of a brooch, carved into the shape of a scarab beetle. The glass sat there undisturbed for four thousand years, until archeologists unearthed it in 1922 in the burial chamber of the pharaoh Tutankhamun, more commonly known as King Tut.

Silica, or silicon dioxide, is a chemical compound that is abundant on our planet. More than 50 percent of Earth's crust is made up of this element, which plays almost no role in the natural metabolisms of carbon-based life-forms (like us) or in technologies that rely on fossil fuels and plastics. One reason evolution didn't find much use for silicon dioxide is that most of the really interesting things about this substance don't appear until it's in temperatures of over 1,000 degrees Fahrenheit. That kind of heat doesn't happen on the surface of the planet without the right technology—which we got once people invented the furnace. By learning how to generate extreme heat in a controlled environment, we unlocked the molecular potential of silicon dioxide, and figured out how to create glass. Soon, the way we saw the world and ourselves was transformed.