Published: Sat, March 10, 2018
Science | By Hubert Green

Super-deep Diamond Contains Earth's Mineral Never Seen Before

Super-deep Diamond Contains Earth's Mineral Never Seen Before

While most of us might value diamonds for their beauty, geologists like the minerals for what they can tell us about the goings on deep within our planet. So much so that it's thought to be the fourth most abundant mineral present inside the Earth. This is because it is typically buried around 650 kilometers (400 mi.) deep within the Earth. Usually, diamonds form due to the effect of heat and pressure at depths of 150-200 kilometers, but diamonds formed at much lower depths are occasionally found, providing invaluable clues into our planet's interior. Pearson explained that the diamonds from the mine are among not only the most commercially valuable in the world, but they are also the most scientifically valuable, providing insight into the deepest parts of Earth's core. And that is because perovskite (calcium silicate, CaSiO3) is not found on the surface at all, and occurs at depths of 700 kilometers (435 miles), in Earth's deep mantle. The mine is located on a well known diamond-bearing kimberlite pipe in the Gauteng Province of South Africa. The mine also holds the distinction of producing the world's largest diamond in 1905.

It was found unexpectedly by Graham Pearson, a professor in the University of Alberta's Earth and Atmospheric Sciences department, along with other researchers from the University of British Columbia.

One of the only ways to actually keep it stable in the surface will be to trap it inside an nearly indestructible and strong container like a diamond, he explained. This mineral is one of those that makes the Earth's mantle.

The rare Earth mineral embedded in the diamond measures only 0.031 millimeters across.

(Motherboard) A new report published today in Science suggests that pockets of liquid water may exist up to 500 miles beneath Earth's surface-far deeper that previous estimates.

The pressure that this particular diamond would have had to undergo before it formed could have been equivalent to about 240,000 atmospheres, he said. When this extreme force formed the diamond, the CaSiO3was trapped inside.

The diamond's structure managed to protect the CaSiO3 and prevented its crystal lattice from being deformed while the diamond moved to the Earth's surface.

This diamond discovery, Pearson said, is "a nice illustration of how science works".

"T$3 he specific composition of the perovskite inclusion in this particular diamond very clearly indicates the recycling of oceanic crust into Earth's lower mantle", Pearson said in the statement. "It provides fundamental proof of what happens to the fate of oceanic plates as they descend into the depths of the Earth", he added.

The researchers polished the diamond and conducted spectroscopic analysis to confirm that the mineral inside it is indeed the perovskite.

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