16 December 2016
Vol 354, Issue 6318

About The Cover

Cover image expansion

COVER Standing at ~7-centimeters tall, this 404.2-carat rough diamond was recovered from the Lulo mine, Angola, in February 2016. Evidence from the interior of such large gem diamonds suggests that these diamonds grow from an iron-nickel metallic liquid in Earth's deep convecting mantle. The presence of metal in regions of the deep mantle has broad implications for Earth's geologic evolution. See page 1403.
Photo: © SPOA/Orel SIMON