Petra Diamonds finds 342.92 carat rough at Cullinan mine

South Africa’s Petra Diamonds (LON:PDL) has recovered a 342.92 carat Type IIa white rough at its iconic Cullinan mine.

The company said the diamond is “exceptional” quality, in terms of both its colour and clarity,  and that it will likely be sold at the September tender.

Petra in March sold a 299.3 carat Type IIA white diamond for $12.2 million.

Type II diamonds are found less frequently and more valuable than Type I diamonds, as they have no measurable nitrogen impurities. This gives them exceptional transparency and brilliance

Cullinan is known as 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.

Cullinan is known as the world’s most important source of blue diamonds, such as the 39.34 carats one Petra found in April and which sold for $40.2 million earlier this month. It was the company’s highest price ever for a single stone.

This item originally appeared on www.Mining.com.