Diamond mined from 1 km depth found with 700-km-deep mineral
In a first, a diamond mined from a depth of less than 1 km in South Africa was found containing calcium silicate perovskite, which is usually formed deep in the mantle about 700 km below the Earth's surface. Researchers said the finding proves that slabs of oceanic crust that sink deep within the Earth are recycled into the lower mantle.