Rare £10 million blue diamond the clearest ever found is discovered in South Africa

A rare blue diamond that might fetch over £10 million when it is sold, and could break world records for its clarity, has been discovered in a mine in South Africa.

The diamond, which came from the famous Cullinan mine 25 miles from Pretoria, is going to be sold at auction soon, but the owners of the mine, Petra Diamonds, don't know how much it will truly be worth until a buyer emerges, saying 'it depends on what people are prepared to pay for it'.

While the diamond still needs further forensic investigation, the company that found it already think they have unearthed a 'very special diamond.'

Blue diamonds are the most coveted in the world thanks to their rarity, and the Cullian mine the most important source for them in the world

Blue diamonds are some of the rarest diamonds in the world, and only make up around 0.1% of all diamonds found every year. Petra Diamonds has only found four blue diamonds since they took over the Cullinan mine in 2008.

How much a diamond is worth is often decided by three factors; the flawlessness, the colour, and the rarity. 

While this latest blue diamond still needs further assessment, it has already been deemed as 'on the large end' and 'exceptional.'

A spokesperson for Petra Diamonds said: 'It's a very special diamond. 

'You don't usually get diamond blues of this size or clarity. There's going to be a lot of interest in it in the diamond buying community.'

CEO of Petra Diamonds Johan Dippenaar holding the coveted stone, which has the potential to yield an incredibly important cut diamond

'The stone is an outstanding vivid blue with extraordinary saturation, tone and clarity.

'It has the potential to yield a polished stone of great value and importance.

'It may well even break new records.'

When the diamond is bought it will likely be cut and polished, meaning it could lose between one third and half of is mass, depending on the quality of the stone. 

Located at the foothills of the Magaliesberg mountain range, the Cullinan mine is 37 miles north-east of Pretoria in South Africa. 

The mine has a history of producing blue diamonds, but its regular yield is mostly small white diamonds, earning its owner a revenue of around £133 million a year from 800,000 carats in total.

The diamond has yet to be cut, a process which will make it significantly smaller, as it involves shaping it, and cutting off a lot of its mass

The Cullinan diamond mine first made waves in 1905 when it unearthed the largest rough gem diamond ever found, a massive 3,106 carats.

This diamond was named 'The Great Star of Africa', and became famous in British culture when it was mounted in the Scepter of the Cross, part of the Queen's crown jewels. 

Other notable diamonds produced by the mine include the Premier Rose, which was 353 carats rough and valued at around $10 million (£6 million), and the Golden Jubilee, 545 carats, worth up to $14 million (£8.5 million) - the largest cut and faceted diamond in the world. 

Cullinan has made a few very important diamond discoveries since 2008 when Petra Diamonds took over the mine, including a 39.9 carat diamond which sold for $8.8 million (£4.8 million), a 26.6 carat diamond which sold for $1.45 million (£881,030) and a 25.5 carat diamond which sold for $16.8 million (£10.2 million) last year.