What Happens Now? Following 29.6 Carats of Vivid Blue Diamond

Image courtesy of Petra Diamonds

Rare discovery

You might have heard in the news that Petra Diamonds recently announced the recovery of a very rare diamond. An exceptional rough, blue diamond weighing 29.6 carats from the Cullinan Mine, South Africa. The diamond has been described as vivid blue, with extraordinary saturation, tone and clarity. 

Vivid blue with extraordinary saturation, tone and clarity

What gives the diamond its blue colour?

What makes the diamond blue? Typically the presence of Boron atoms. The higher the concentration, the result is a more intense blue.

Does the blue diamond have a name?

At this time, the diamond has not been named.

Where was the diamond discovered?

The rare blue diamond was discovered at the Cullinan mine, 37 kilometres north-east of Pretoria, in South Africa. Cullinan is one of the most famous, historic and celebrated diamond mines. Cullinan is renowned as the world’s most important source for blue diamonds. Most famous for the discovery of the largest rough diamond weighing 3,106 carats, yielding the 530 carat Star of Africa [mounted in the Sovereign’s Sceptre] and the 317 carat Second Star of Africa. The mine has produced over 750 stones weighing more than 100 carats, 130 diamonds weighing over 200 carats. A quarter of the World’s rough diamonds over 400 carats are from the Cullinan mine. Petra diamonds acquired the mine in 2008 and has produced some of the rarest blue diamonds discovered to date.

Holding the 29.6 carat rough blue diamond. Image courtesy of Petra Diamonds.
Holding the 29.6 carat rough blue diamond. Image courtesy of Petra Diamonds.

How was the diamond recovered?

The diamond process at Cullinan is highly mechanised. Petra mine 2 – 3 million tonnes of ore from below the ground each year, using enormous machinery. Ore, brought to the surface passes through a processing plant, crushing rock into progressively smaller sizes at each stage of the operation. The final stage is the final recovery section. This tends to be a hands-free automated section, using X-ray technology to separate diamonds from other material. The final recovery is undertaken under very high levels of security.

What is the value attached to this new 29.6 carat diamond?

A representative of Petra Diamonds told us that this diamond could be in a class of its own. The only way to appreciate the value at this stage is to look at previous diamond sales that have been made. It is interesting to note that the 25.5 carat blue diamond from Cullinan was sold in 2013 for US$16.9 million or US$663k per carat. This is the highest price achieved by Petra in its history.

What will happen to the diamond now?

Petra will sell the diamond (in the rough – i.e. before cutting and polishing). Selling the diamond as a rough stone is considered the optimal route to market not only due to the high value expected, but also to the immediate effect the sale has on cashflow. Owing to Petra’s capital intensive development programmes, realising immediate revenues from the diamond will maximise value for shareholders.

Mark Johnson

About Mark Johnson

Mark attended Liverpool University and went on to pursue a career in the diamond industry. After more than a decade working in polished diamonds, Mark moved to the Isle of Wight where he launched Serendipity Diamonds. He works most days from their busy Ryde showroom, photographing jewellery and writing for the Serendipity Diamonds website. Anyone interested can connect with Mark on Linkedin via the profile link.

Mark Johnson

About Mark Johnson

Mark attended Liverpool University and went on to pursue a career in the diamond industry. After more than a decade working in polished diamonds, Mark moved to the Isle of Wight where he launched Serendipity Diamonds. He works most days from their busy Ryde showroom, photographing jewellery and writing for the Serendipity Diamonds website. Anyone interested can connect with Mark on Linkedin via the profile link.