This article is taken from Science et Avenir – La Recherche n ° 899, dated January 2022.

A new mineral composed of calcium, silicon and oxygen has been discovered in a diamond mined at a mine in Botswana. Named “dawemaoite” in honor of Sino-American geophysicist Ho-Kwang Dave Mao, who predicted its existence, it was synthesized in the laboratory in 1975 but had never been observed in nature until now. The mineral only forms in the inner mantle at depths between 600 and 900 km, where the pressure is 200,000 times greater than at the surface.

an essential role in heat transport

As it rises in the upper mantle and crust, where the pressure is very low, devomoite transforms into other compounds. This sample was able to retain its structure by being trapped in the diamond. According to researchers from the University of Nevada (United States) Science, devomalite will account for between 5 and 7% of the lower mantle’s minerals and will play an essential role in the transport of heat from Earth’s depths, a process that feeds the plates’ tectonics.