Diamonds reveal hidden chemistry deep inside Earth

South African diamonds have revealed nickel-rich metallic inclusions, offering the first direct evidence of reactions predicted to occur deep in Earths mantle. The study shows how oxidized melts infiltrated reduced rocks, trapping both the cause and effect of diamond formation. These reactions help explain volatile-rich magmas like kimberlites, linking mantle chemistry to volcanic processes. Diamonds emerge as tiny record-keepers of Earths deep, dynamic engine.