Graphitized diamonds from a peridotite massif in Morocco and implications for anomalous diamond occurrences

DIAMONDS are found in several areas of the world where their currently accepted source, kimberlite/lamproite volcanism, has not been found. Garnet pyroxenite layers in the the Beni Bousera peridotite massif, northern Morocco, contain octahedral and other cubic forms of graphite, which we interpret here as pseudomorphs after diamond. This occurrence demonstrates that fragments of highly diamondiferous mantle are technically emplaced into the continental crust, providing an alternative source for some diamonds.