Surprised scientists discover new mineral on Earth's surface

Davemaoite hitched a ride inside a diamond, traveling all the way up from the planet's lower mantle.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
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This diamond protected the davemaoite mineral and allowed it to emerge on the surface of Earth.

Aaron Celestian, Los Angeles County Natural History Museum

Quartz. Feldspar. Mica. Fluorite. You don't need to be a geologist to recognize a lot of the common, familiar minerals on Earth. But what about davemaoite? It's OK if you've never heard of it. It's a new discovery.

A team of geochemists found the mineral in dark inclusions inside a diamond. "There's just one catch: it shouldn't be here," said the University of Nevada, Las Vegas in a statement Monday. The researchers traced the mineral to at least 410 miles (660 kilometers) down inside the planet's lower mantle between the core and the crust.

UNLV said it's "the first time that lower mantle minerals have ever been observed in nature." The mineral was fortuitously preserved in a diamond mined from Botswana and sold by a gem dealer in 1987. Davemaoite would normally not be able to retain its structure outside of the high-pressure environment of the Earth's mantle, but diamonds are famously strong. 

"For jewelers and buyers, the size, color, and clarity of a diamond all matter, and inclusions — those black specks that annoy the jeweler — for us, they're a gift," said mineralogist Oliver Tschauner. "I think we were very surprised. We didn't expect this."    

Tschauner is the lead author of a study on the mineral published in the journal Science last week. The researchers analyzed the diamond's interior structure and found the calcium silicate compound (CaSiO₃-perovskite) inside. They named it "davemaoite" for pioneering geophysicist Ho-kwang "Dave" Mao.

The International Mineralogical Association approved the new natural mineral and added it to its list of minerals. You might not be able to add davemaoite to your personal rock collection, but you can admire its remarkable journey into the hands of science.