Scientists just uncovered a rare “super-deep” diamond in South Africa that’s wrapped in calcium silicate perovskite – the fourth-most abundant mineral found on Earth. It’s a significant discovery because, despite the mineral’s abundance, this marks the first time calcium silicate perovskite has been found in nature. “This was very special because this mineral had been theoretically predicted, but it was not thought possible to see it preserved at the Earth’s surface for observation and measurement,” study co-author Graham Pearson told Inverse. “Finding a natural object that has never been seen by anyone before is always exhilarating! It’s what most natural scientists dream about.”
The discovery was made at Cullinan mine in Gauteng province – a mine known for its rare blue diamonds as well as its scientific and commercial value. According to the authors of the study published in Nature, diamonds “provide access to the deepest intact material from the Earth’s interior through the minerals contained within their volumes.” The discovered diamond is called “super-deep” in reference to its origins 200 to 1,000 kilometers (about 125-621 miles) below the surface of the Earth, The first-ever natural discovery of calcium silicate perovskite (CaSiO3) wrapped in a rare diamond is providing scientists with a privileged glimpse into the deep inner workings of the Earth.
The super-deep diamond was determined to have formed approximately 760 kilometers below the surface of the Earth. Because the diamond formed in such a deep location, it was highly pressurized. This enabled the diamond to successfully hold CaSiO3, which exists only in very high pressure environments. “Only the super-strong nature of the diamond, and the particular nature of the fast eruption of the host kimberlite, in this case, provided a favorable set of circumstances that led to the preservation of this mineral,” explained Pearson. “Many people predicted that we would never actually see a natural version of this mineral at the Earth’s surface because it is so unstable.”