What’s hidden in a diamond in the depths of the Earth

The sample is at least 660 kilometers deep. Confirmed existence of calcium silicate perovskite in our planet's lower mantle.

At least 660 kilometers deep, there is calcium silicate perovskite in Earth's lower mantle. The confirmation came from a team of scientists, and their study was published in the journal Science. Embedded in a diamond, the mineral has been named davemaoite. The scholars also predicted that calcium silicate perovskite is the fourth most abundant mineral on Earth, but it has so far been completely beyond our reach.

The mineral hidden in a diamond at the center of the Earth

Calcium silicate perovskite can be created in the lab using a laser to simulate high pressures, but once the pressure is removed, its cubic shape falls apart. Because of this, until now, it has not been possible to find the mineral in its natural form. What preserves the material intact is the diamond in which it is hidden. Lead author of the research, Dr. Oliver Tschauner, of the University of Nevada at Las Vegas, explained that "the discovery is the result of decades of effort and the development and use of microanalytical techniques to identify micron-scale structures and compositions in diamonds."

Calcium silicate perovskite properties

The Nevada researchers' study highlighted some interesting properties of the mineral. In particular, the team focused on the crucial role played by the incredible pressure at which calcium silicate perovskite forms. "Structural and chemical analysis of the mineral has shown that it is capable of hosting a wide variety of elements," the team wrote in a paper, "in particular, it has a large amount of trapped potassium."

Previously, it had been shown experimentally that such material can be a kind of "garbage can," meaning it could host radioactive uranium and thorium. Along with potassium, these are the three main heat-producing elements. The abundance of davemaoite and its valuable deposit would be evidence that the mineral contributes to heat creation through the deepest layer of the mantle.

Davemaoite is the second high-pressure generated silicate mineral confirmed in nature. The only other known one is called bridgmanite, found inside a meteorite. Scholars now hope to find other minerals that exist only at high pressures.

Still on the subject of what's deep inside our planet, another research has identified a "new world" in the Earth's inner core, while a team of scholars has speculated that the globe may have formed around the core of an alien rock.

Stefania Bernardini