Petra Diamonds Unveils Five High Quality Blue Diamonds From The Cullinan Mine

As time passes by, it is apparent that finding blue rough diamonds becomes more challenging. We also know that the vast majority and the rarest blue diamonds come from the Cullinan Mine in South Africa. 

Petra Diamonds unveiled five high quality blue diamonds from its mine exactly a year after its last major find at the mine. The five diamonds weigh a total of 85.6 carats (25.75 carats, 21.25 carats, 17.57 carats, 11.42 carats and 9.61 carats).

The last time Petra Diamonds extracted a blue rough diamond was in September 2019. It weighed 20.08 carats, and was sold in November for $14.9 million or $741,000 per carat. At the time, the buyer decided to remain anonymous (but Petra mentioned in its press release that the buyer was a leading diamond company). From the sale price it seems clearly that the polished diamond will yield a Fancy Vivid Blue diamond, otherwise, it will be a complete financial disaster. Up to now, no diamond company has announced its ownership or the outcome of the rough diamond.

In this case, I wonder if Petra Diamonds will sell each individual diamond by itself or if it will sell them all together as a single lot. The second question would be the potential sale price. Based on the pictures and without having inspected the diamonds, the initial indication is that they will definitely be in the Fancy color spectrum of intensities, so either Fancy Blue, Fancy Intense Blue or Fancy Vivid Blue. This means that the valuation will be greatly different.

We also have to take into account the loss of rough material to get to the polished version. On average, the loss of weight falls between 50-65% from the rough. If we take the 20.08 carat and remove the average of 50-65% of the weight, we end up with 7-10 carats. Based on this and the fact that it will end up being a Fancy Vivid Blue diamond, it will most likely sell for between $20-$35 million on a retail basis which means a significant return on investment. Based on the risk involved with polishing such a diamond, the return is justified.