An exceptional 29.6 carat blue diamond has been discovered in the Cullinan mine in South Africa.
The diamond is very rare and is described as being of a vivid blue with extraordinary saturation, tone and clarity.
The 29.6-carat stone was recovered by Petra Diamonds at its Cullinan mine, about 40km (25 miles) north-east of Pretoria.
According to the mining company "this stone is one of the most exceptional stones recovered at Cullinan during Petra's operation of the mine".
Previously, Petra unearthed a 25.5 carat blue diamond which sold for $16.9m (£10.3m) in 2013.
It is expected that this new finding will be much more expensive.
"The stone is an outstanding vivid blue with extraordinary saturation, tone and clarity, and has the potential to yield a polished stone of great value and
importance," Petra said in a statement on Tuesday.
The mining company Petra Diamonds has discovered a number of beautiful and stones in the past and it famed for the production of blue diamonds.
A similar 26.6-carat blue rough diamond discovered by the company in May 2009 was cut into a near perfect stone and fetched just under
$10m at a Sotheby's auction.
Image taken Friday Jan. 18, 2014 and made available by Petra Diamonds of a 29.6 carat blue diamond which was recovered at the
Cullinan Diamond Mine near Pretoria, South Africa. The stone is described as being of a vivid blue with extraordinary saturation ,
tone and clarity, and has the potential to yield a polished stone of great value and importance.
(AP Photo/Philip Mostert - Petra Diamonds)
Another deep-blue diamond from Cullinan was auctioned for $10.8m in 2012 and set a world record for the value per carat.
The largest ever rough gem diamond was discovered at the Cullinan mine in 1905 and was presented to the British monarch Edward VII.
The 3,106-carat stone was then cut, with two of the principal diamonds forming part of the British crown jewels. The 530-carat 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.
CEO of Petra Diamonds Johan Dippenaar holding the coveted stone, which has the potential to yield an incredibly important cut diamond.
This beautifully rare blue diamond must now undergo forensic tests. Later, it 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
It is estimated the blue diamond will cost over £10 million when it is sold, and could break world records for its clarity,