Mineral hints at bright blue rocks deep in the Earth

Minerals preserved in a diamond from a 100 million year old Kimberlite found in Brazil have revealed hints of the bright blue rocks that exist deep within the Earth.It also provides the first direct evidence that there may be as much water trapped in those rocks as there is in all the oceans.

The diamond contains minerals that formed as deep as 600km down and that have significant amounts of water trapped within them.

Diamonds, brought to the Earth's surface in violent eruptions of deep volcanic rocks called Kimberlites,
provide a tantalising window into the deep Earth.

The diamond contained a mineral, Ringwoodite, that is only thought to form between 410km and 660km beneath the Earth's surface, showing just how deep some diamonds originate. While Ringwoodite has previously been found in meteorites, this is the first time a terrestrial Ringwoodite has been seen. But more extraordinarily, researchers found that the mineral contains about 1% water.

While this sounds like very little, because ringwoodite makes up almost all of this immense portion of the
deep Earth, it adds up to a huge amount of deep water - up to several times the amount in the Earth's Oceans.