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New mineral 'davemaoite' made an unlikely journey from the depths of the Earth

Researchers say they've recovered a mineral from deep inside the Earth — one they thought would never see the light of day.

Scientists at the University of Nevada, Las Vegas, named the mineral "davemaoite," after Ho-kwang "Dave" Mao, a retired experimental geophysicist whose influence on the field is still felt today.

"It's an opportunity to give him credit for his big contributions," said Oliver Tschauner, a mineralogist who led a study of the rare mineral, in an interview with NPR's Morning Edition.

No one ever expected to see the mineral on the Earth's surface.

That's because deep-Earth minerals like davemaoite aren't suited to survive outside the high-pressure environments where they're made. But this sample of davemaoite did survive. Trapped inside a diamond, the mineral made the more than 410-mile journey to the Earth's surface from its lower mantle — the layer between the planet's core and crust. Without the diamond's strength, the davemaoite would've fallen apart.

"That was, a little bit of luck that we found it," said Tschauner.

Scientists in 1975 had previously theorized that the crystalized compound, calcium silicate perovskite, existed within the Earth's mantle. But now they have proof, marking "the first time that lower mantle minerals have ever been observed in nature," according to a news release from the university on Monday.

The diamond-encased mineral was mined in Botswana before a gem dealer sold it to a mineralogist at the California Institute of Technology in Pasadena.

The mineral was spotted among tiny inclusions — or specks — within the diamond.

"Jewelers, of course, want the flawless diamond — the one that does not have any inclusions," said Tschauner.

When Tschauner and his team finally got hold of the rarity, they used what he described as a specialized X-ray, known as a synchrotron, to study it.

The finding will help scientists get a clearer picture of the evolution of the Earth's mantle, according to Tschauner. Scientists also believe davemaoite plays a key role in generating heat flow in the Earth's mantle, which in turn drives processes such as plate tectonics that reshape the Earth's landmasses.

And it's official: Last year, before Tschauner's team published their findings, the International Mineralogical Association added davemaoite to its list of minerals. As for the sample itself, it's now in safe-keeping at the Los Angeles Natural History Museum.

Copyright 2021 NPR. To see more, visit https://www.npr.org.