Unclassified silicate, bridgmanite group
Specific gravity: 4.20 calculated
Environments: Included in a diamond from a kimberlite pipe
Davemaoite is a new mineral, approved in 2020 and to date (June 2022) reported only from the type locality. It is an extremely high pressure mineral, formed at pressures obtaining in the lower mantle.
The type locality, the AK-8 kimberlite pipe, Orapa, Letlhakane, Central District, Botswana, is in one of the world’s largest diamond mines Davemaoite is a perovskite mineral that was found as an inclusion in an octahedral diamond. The diamond was later cut and polished to bring the inclusions closer to the surface for experimental analysis. Davemaoite occurs with carbonaceous α-iron and wüstite, and other inclusions in the diamond include ilmenite, iron, and ice-VII. Remnant pressure in the diamond is estimated to be between 7 and 9 GPa.
The davemaoite preserved in the diamond is the first known high-pressure silicate mineral recovered from the lower mantle. Previously, no one had observed CaSiO3-perovskite from the lower mantle. Synthetic CaSiO3-perovskite has been shown to lose its crystal structure upon decompression from high pressure. The only other high-pressure silicate mineral found from lower-mantle pressures to date was bridgmanite (MgSiO3-perovskite) but that was found inside a meteorite. (AM 107.778).
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