Petra fetches over $40m for 39-carat blue diamond

A 39.34-carat blue diamond. (Image courtesy of Petra Diamonds.)

South Africa’s Petra Diamonds (LON:PDL) has fetched $40.2 million for a 39.34-carat blue diamond it recovered at its iconic Cullinan mine in April, the company’s highest price ever for a single stone.

It means the buyer, a partnership between diamond giant De Beers and Diacore, paid $1,021,357 per carat.

“This new milestone for Petra follows the sale of the 299 carat Type IIa white diamond in March this year and the five blue diamonds comprising the Letlapa Tala Collection in November 2020,” chief executive Rihard Duffy said in the statement.

Petra’s Blue Moon of Josephine diamond, cut from a 29-carat rough blue diamond, sold for $48.5 million in 2015.

The figure corresponds to a price of $4 million per carat, which remains the world record price per carat ever paid for a diamond at an auction.

Cullinan is known as the world’s most important source of blue diamonds, as well as being the birthplace of the 3,106-carat Cullinan diamond, which was cut to form the 530-carat Great Star of Africa. The operation also yielded the 317-carat Second Star of Africa. They are the two largest diamonds in the British Crown Jewels.

Type IIb blue diamonds are so rare that their age has not been established. Recent studies on minerals trapped inside these diamonds imply that they are among the deepest-formed diamonds ever found, created at depths in excess of 500km below the Earth’s surface.