Diamonds serve almost unlimited functions on our Earth. Cut and polished they make beautiful additions to jewelry and have become a tradition in engagement rings. Loose diamond dust is saved for use in tools and industry for such items as saw blades and wires. As the hardest substance known to man, diamonds are extremely useful in many applications.
Recently, a new application has been found – research into the materials that originally formed the earth with the discovery of diamonds that contain the mineral calcium silicate perovskite, the fourth most abundant mineral found in the Earth. Scientists have been aware of the mineral for some time but have never been able to bring it to the surface in its true form. By the time it reaches a diggable level the pressures subside and the molecules change. Encased in a diamond, it is protected and scientists are able to study the mineral exactly as it exists deep below the Earth’s surface.
Most diamonds are mined in Brazil or South Africa about one hundred miles below the surface, but those that contain the elusive mineral are formed almost three hundred miles down in the Earth’s mantle and quickly come to the surface during a major volcanic event. The appearance of calcium silicate perovskite indicates an ancient lava reservoir deep in the Earth that has been unchanged for over four billion years, which is remarkable considering the Earth has been constantly changing for billions of years as the tectonic plates slide.
The mineral was found by a group of scientists led by Dr. Suzette Timmerman of the Australian National University by measuring helium isotopes trapped inside the diamond. Timmerman has indicated these diamonds will assist in better understanding of the lower mantle which is virtually impossible to study. The discovery also raises more questions as to whether the reservoir is single or made up of pockets. The locations of the reservoirs as well as the chemical composition have not yet been determined. The high ratio of helium 3 to helium 4 isotope is also found in old meteorites discovered on Earth.
The transition zone has also produced diamonds containing ringwoodite, a mineral composed of one and a half percent water present as hydroxide ions. The diamonds were found in 2014 in South Africa’s Cullinan Mine owned by London’s Petra Diamonds, the black economic empowerment group Thembinkosi Mining Investments and Saudi-based investment company Al Rajhi Holdings according to Cullinan Diamonds website. These diamonds suggest there may be large areas of water below the mantle. Professor Graham Pearson from the University of Alberta and his team are testing these diamonds for age and according to National Geographic, they are currently estimating they could be as much as a billion years old. The Cullinan Mine in the Gauteng Province of South Africa has produced some of the largest diamonds in the world including the over three thousand carat Star of Africa, many of the British crown jewels and is also a source for rare blue diamonds. Cullinan Mine also certifies their diamonds as conflict-free.