Petra achieves $13.5m for 342 and 18 carat diamonds
Discovered at the Cullinan Diamond Mine in South Africa, the diamonds have been sold into a partnership with Stargems

Jersey-based mining group Petra Diamonds has announced the sale of a 342.92 carat Type IIa white diamond and an 18.30 carat Type IIb blue diamond have been sold for $13.5m (£9.82m).