Exceptional' 122.52 carat blue diamond found in South African Petra mine

Exceptional' 122.52 carat blue diamond found in South African Petra mine

In what is shaping up to be one of most the amazing diamond finds in recent times, a 122.52 ct. blue diamond—the size of a walnut—has been discovered at the Cullinan mine in South Africa, said mine owner Petra Diamonds.

The vast majority of blue diamonds owe their color to the presence of boron. The bonding of boron to carbon causes absorption in the red, yellow and green parts of the spectrum producing a blue color. Blue Diamonds may contain a gray, violet or greenish modifying color.

A blue diamond weighing a staggering 122.52 carats has been unearthed in South Africa - expected to be the most valuable ever found. Petra Diamonds Ltd said it had recovered the 'exceptional' gem at its Cullinan mine, on the outskirts of Pretoria, just months after it sold a 29.6 carat blue diamond from the same mine for more than £14 million ($25 million).

The jewel - which is about the size of a strawberry - is so pure that it is expected to eclipse the current world's most expensive diamond - a 507-carat white diamond dug from the same mine that sold for £20 million in 2010. Blue diamonds are considerably more valuable than their white cousins. Petra, which acquired the famed diamond mine in 2008, said it would evaluate the optimal route to market for the stone after a further analysis to assess its potential value.

'So far, the highest price on record paid for a rough diamond was £20 million ($35.3 million), paid in February 2010 for a 507 carat white stone, also recovered from Cullinan. We think that this stone may break that record,' finnCap analyst Martin Potts said.