A diamond discovered deep beneath Earth’s surface contains a mineral that has never been found before on our planet. The mineral has been named davemaoite after geophysicist Ho-kwang (Dave) Mao.
While davemaoite is the first ever discovery of a high-pressure calcium silicate perovskite (CaSiO3) on our planet, another CaSiO3 named wollastonite is plentiful on Earth. Davemaoite, however, can only form by high temperatures and a lot of pressure in the mantle of our planet.
It was long believed that Earth did contain davemaoite but experts never found any evidence of it – until now. Since davemaoite breaks into different minerals as it gets closer to the surface, finding proof of it is exceptionally difficult, but a diamond in Botswana has finally provided scientists with the evidence they needed.
The diamond formed in Earth’s mantle approximately 410 miles (660 kilometers) below the surface. And inside of the stone was a very tiny piece of davemaoite – only a few micrometers (millionths of a meter) in size. Oliver Tschauner, who is a mineralogist at the University of Nevada, Las Vegas, and his colleagues, used synchrotron X-ray diffraction in order to find the never-before-seen mineral inside of the diamond. In an interview with Live Science, Tschauner stated that the discovery “...came as a surprise”.
Since scientists believe that davemaoite might contain additional elements that can give off heat by radioactive decay (such as thorium and uranium), the mineral could possibly aid in providing a significant dose of heat in Earth’s mantle. Additionally, this means that diamonds can grow much farther down below Earth’s surface than previously believed and these stones could possibly lead to even more discoveries of never-before-seen minerals.
Yingwei Fe, who is a geophysicist at the Carnegie Institution for Science in Washington, D.C., but was not part of the study, weighed in on the discovery by saying, “The work by Tschauner et al. inspires hope in the discovery of other difficult high-pressure phases in nature.” “Such direct sampling of the inaccessible lower mantle would fill our knowledge gap in chemical composition of the entire mantle of our planet.”
The discovery has led the International Mineralogical Association to confirm davemaoite as being a new mineral. A picture of the diamond that contained davemaoite can be viewed here.
The study was published in the journal Science where it can be read in full.