'Exceptional' 122ct Blue Diamond Discovered
A mining firm has revealed the discovery of an "exceptional" 122.52-carat blue diamond.
Petra Diamonds said the discovery was made at the Cullinan mine in South Africa.
The London-based firm saw its share price rise more than 6% in early Friday trades as a result of the announcement.
It said in a statement: "The rarity of a blue diamond of this magnitude sets it apart as a truly significant find.
"The stone will require further analysis in order to assess its potential value and upon completion of this process, Petra will be in a position to evaluate its optimal route to market.
"The diamond will, therefore, not be sold before the end of the company's current financial year (June 30)."
The Cullinan mine is known as the world's most important source of blue diamonds and was purchased by Petra in 2008.
It is located at the foothills of the Magaliesberg mountain range, 24 miles north-east of the capital Pretoria.
The mine gained international fame in 1905 after the discovery of the largest rough diamond ever discovered, weighing 3,106 carats.
It was cut into two dressed diamonds for the British monarchy.
The First Star of Africa, weighing 530 carats, was mounted atop the Sovereign's Sceptre.
It is the largest flawless cut diamond in the world.
The Second Star of Africa, weighing 317 carats, is centrally located in the Imperial State Crown.
There are no official statistics on the recovery and dressing of rare blue diamonds.
The blue hue is because of small traces of boron trapped in the carbon structure during formation.