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Megadiamonds point to metal in mantle

Glimpse of deep Earth chemistry found in rare gems’ imperfections

diamond

DEEP DIVE Metal shards (black spots) in this diamond hold clues to the deep-Earth environment in which it formed.

Jae Liao

By Laurel Hamers

- More than 2 years ago

Imperfections in supersized diamonds are a bummer for gem cutters but a boon for geologists. Tiny metal shards embedded inside Earth’s biggest diamonds provide direct evidence that the planet’s rocky mantle contains metallic iron and nickel, scientists report in the Dec.