'Oceans' underneath the Earth's crust

Scientists have found the first terrestrial sample of a water-rich gem suggesting large volumes of water deep underneath the Earth. An international team of scientists led by Graham Pearson at Canada Excellence Research Chair in Arctic Resources at the University of Alberta has discovered the first-ever sample of a mineral called ringwoodite. Analysis of the mineral shows it contains a significant amount of water — 1.5%, of its weight — a finding that confirms scientific theories about vast volumes of water trapped 410 to 660 kilometers beneath the Earth, between the upper and lower mantle. The diamond had been brought to the Earth's surface by a volcanic / rock known as kimberlite — the most deeply derived of all volcanic rocks. Pearson said the discovery was almost accidental in that his team had been looking for another mineral when they found a three-millimetre-wide, dirty-looking, commercially worthless brown diamond. The ringwoodite itself is invisible to the naked eye, buried beneath the surface, so it was fortunate that it was found by Pearson's graduate student, John McNeill in 2009. The sample underwent years of analysis using Raman and infrared spectroscopy and X-ray diffraction before it was officially confirmed as ringwoodite. [TOI, 14, March, 2014] +++++++++++++++++++++++++++++++++++++++++++++++++++