Rough blue diamond: In February 2014, Petra Diamonds sold one of the world’s most important blue diamonds. Their uncut 29.62-carat blue diamond, recovered from the Cullinan mine in South Africa, sold for $25,555,555 USD (a price of $862,789 USD per carat). The Cullinan mine is the source of some of the world’s most famous diamonds, the most important source of blue diamonds, and the mine where the two main diamonds in the British Crown Jewels were produced. Photograph by Petra Diamonds.
Yellow diamond crystal: In December 2017, Alrosa announced the recovery of a 98.63-carat yellow-tinged octahedral diamond crystal from the Jubilee (Yubileynaya) Pipe, Sakha Republic, Russia. The crystal measures approximately 29 x 28 x 27 millimeters and contains inclusions of olivine, graphite, and sulfide minerals. During calendar year 2017, Alrosa recovered more than 20 large rough diamonds with a weight of over 50 carats from the Jubilee Pipe. This diamond crystal is extremely interesting. Its surface is covered with growth lines and trigons. Click to enlarge. Photographs by Alrosa.