In what sounds like a chapter from Journey to the Center of the Earth, the chemical makeup of a tiny, extremely rare gemstone has made researchers think there's a massive water reservoir hundreds of miles under the earth.
The gemstone in question is called ringwoodite, which is created when olivine, a material that is extremely common in the mantle, is highly pressurized; when it’s exposed to less pressurized environments, it reverts into olivine. It has previously been seen in meteorites and created in a laboratory, but until now it had never been found in a sample of the earth’s mantle.
Diamond expert Graham Pearson of the University of Alberta came across a seemingly worthless, three-millimeter piece of brown diamond that had been found in Mato Grosso, Brazil, while he was researching another type of mineral. Within that diamond, he and his team found ringwoodite—and they found that roughly 1.5 percent of the ringwoodite’s weight was made up of trapped water. The findings are published in Nature.
