Analysis of a ‘super-deep’ diamond from Orapa, Botswana, has revealed tiny crystals of a never-before-seen mineral trapped inside.

Davemaoite, named after geophysicist and deep-earth scientist, Ho-kwang (Dave) Mao, is the first example of a high-pressure calcium silicate perovskite (CaSiO3) found on Earth. Its crystalline structure forms only under high pressure and high temperatures in Earth’s mantle, the mainly solid layer of Earth between the outer core and the crust.

Normally, Davemaoite’s crystal structure would break apart if it was brought up to Earth’s surface because of the massive drop in pressure. But because it was trapped inside a rigid diamond, it was preserved on its long journey up to the Orapa mine, which probably took between 100 million to 1.5 billion years.

Most diamonds form 120 to 250 kms underground, but those of the super-deep variety are born in Earth’s lower mantle, which begins 660 kms below the surface.

Davemaoite makes up around 5-7% of the material in Earth’s lower mantle, and is important because it can host radioactive elements like uranium, thorium and potassium-40 that heat Earth as they decay.

Picture Credit : Google 

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