Deep beneath our feet, hundreds of kilometers down, lies the rock davemaoite. Its crystal lattice resembles a bent stick: one side is longer than the other. When the rock heats up, the stick straightens and becomes even. This changes how seismic waves pass through the rock, the very waves we feel during earthquakes.
Previously, scientists thought davemaoite straightened at 600 degrees. But new experiments with laser heating show it takes 1470 to 1990 degrees, depending on depth. And if the rock contains titanium impurities, the temperature is even higher, by 600–700 degrees. In a cold oceanic plate sinking into the mantle, davemaoite may remain bent down to depths exceeding 2000 kilometers.
So rock in Earth's depths acts like a thermostat: it only switches its shape at very high temperatures. Thanks to the new data, we better understand what happens deep beneath us.
Davemaoite was officially recognized as a mineral only in 2021, although its existence in the lower mantle had been hypothesized for decades. The name honors geophysicist Ho-Kwang (David) Mao, who made enormous contributions to the study of minerals at high pressures.