The article is totally misleading. There is no way to get at this water, and it has never been directly sampled.
In fact, it is not even water, but just OH, which is part of water and could be made to recombine to produce hydrogen and water — however, all this is far beneath the surface of the Earth, in the middle part
of the mantle, hundreds of km down. By comparison, humans have never even drilled through the mantle of the earth, which is as thin as 5 km in ocean basins.
It is as even more impossible and impractical to get at this water directly as it would be to ship minerals here from the moon, which is another nutty idea one occasional sees featured in journalism of the grocery-store check-out-line level.
The mineral ringwoodite (mentioned in the article) is stable at pressures around 20 GPa. By comparison, the atmospheric pressure at the Earth’s surface is 100 kPa. So ringhwoodite exists at pressures about 20 million times that of the surface (if I have my zeros right).
But perhaps it would be fun to start a movement against fracking for ringwoodite-water, just to divert those who fear fracking in the crust of the Earth, or those afraid of genetically modified organisms.
An idea also vociferously espoused by the FR space kadet contingent along with colonizing Mars and colonizing the moon and other unfeasible stuff.
Thanks docbnj!