“Robert Hazen, a mineralogist at the Carnegie Institution for Science, and his colleagues tallied up the number of minerals on Earth only to discover that a large number have been created, thanks to human activities. Although minerals, by definition, must form via natural processes, Hazen’s team discovered 208 minerals mediated by humans—they did form naturally but in places such as man-made mines, where unnatural humidity or fires from mining operations created new minerals along the mine walls. Other examples might be even harder to find, unless you are a deep-sea diver; when bronze or brass artifacts sink in a shipwreck, for example, they interact with the seafloor to create novel, man-mediated minerals.

“Perhaps more striking are mineral-like compounds—substances that would be characterized as minerals if they were not completely man-made (rather than human-mediated). Hazen’s team created a long list of these as well—everything from synthetic rubies and diamonds to ceramics, brick, cement, batteries and certain components of cell phones—and they suspect there are hundreds of thousands of varieties, too many for them to count.

“Such dramatic changes will not go unnoticed if a future geologist finds herself digging up layers of sediment from an ancient city. “These are the real global marker of our age,” Hazen says. Not only because a city’s infrastructure contains many of these man-made minerals but because it also contains natural minerals that were quarried in locations across the world, creating concentrations that would not be found naturally. Even if sea levels rise 300 feet and cover coastal cities, those minerals will still be visible in the sedimentary record. That’s because landmarks like the Washington Monument and the Smithsonian will collapse into piles of rubble—signatures that are later preserved as highly unusual lens-shaped pockets underground, distinct from their surroundings in both shape and minerals. The Washington Monument, for example, will eventually be a lens-shaped pocket composed of limestone where no other limestone is found. And the pocket that was once the Smithsonian will contain so many rare minerals that they could not possibly have formed so close together in nature. To boot, they will be surrounded by the vast array of the man-made minerals we use every day. “There is nothing at all like this in the geology of the past 4.5 billion years on Earth,” Zalasiewicz says. “It is tragically different.”

Text: Shannon Hall, Found: Thousands of Man-Made Minerals—Another Argument for the Anthropocene, Scientific American.

Pic: “Fordite, also known as Detroit agate or Motor Agate, is old automobile paint which has hardened sufficiently to be cut and polished. It was formed from the buildup of layers of enamel paint slag on tracks and skids on which cars were hand spray-painted (a now automated process), which have been baked numerous times.” – Wikipedia