The image above shows the mineral called ringwoodite, and it’s peculiar because of its pressurized water content. Recent studies show that deep in the Earth’s mantle, encased in a shell of rare minerals, lies a vast ocean, whose overall volume may well be equal or greater than that of all the oceans on the Earth’s surface. Ringwoodite proves its existence, because this mineral only forms under conditions of the mantle, yet in presence of water.