Petra Diamonds has sold two diamonds for a nice bundle: According to Rough & Polished, a 342.92 carat Type IIa white diamond and an 18.30 carat Type IIb blue diamond, both recovered at the Cullinan Diamond Mine in South Africa, were sold for $13.5 million for a partnership with Johannesburg-based Stargems.

Petra received an upfront payment of $10 million for the 342.92 carat stone and $3.5 million for the 18.30 carat diamond. It also retained a “50% interest in the profit uplift of the polished proceeds of both diamonds, after costs,” according to the report.

Petra’s CEO Richard Duffy remarked: “We are delighted that both stones will be manufactured in South Africa and it is fitting that we will be working with Stargems, who specialise in the sourcing and supply of the finest diamonds to customers across the world.”