This is really deep, man: SA diamond came from 660km below surface
The 20-carat stone is rare and incredibly valuable
A diamond mined in SA was formed in Earth’s lower mantle, three times deeper than most diamonds.
The stone in question – its precise origin has not been revealed – weighed 20 carats (about 4g), and a laser aimed at tiny inclusions inside it proved they were created by bridgmanite.
This substance, which makes up about 40% of the Earth’s volume, occurs only under the extreme pressure conditions of the lower mantle, more than 660km below the surface...