An “exceptional” vivid blue diamond weighing 29.6 carats and worth up to $20 million has been unearthed at South Africa’s legendary Cullinan mine — the same mine that has given birth to some of the largest and most valuable diamonds in the world.
Petra Diamonds spokesperson Cathy Malins told AFP that the acorn-sized stone could be “in a class of its own.” Displaying extraordinary saturation, tone and clarity, the rough diamond has the potential to yield a polished stone of great value and importance, mine owner Petra Diamonds noted in statement.
Holding the rough diamond between his thumb and forefinger, Petra Diamonds chief executive Johan Dippenaar commented, “By some margin... this is probably the most significant [blue] stone we’ve ever recovered.” Petra took over the operation of the Cullinan mine in 2008.
Owing their intoxicating blue color to trace amounts of boron impurities in their chemical makeup, blue diamonds are extremely rare, highly coveted and very expensive.
Analyst Cailey Barker told the Huffington Post that Petra’s extraordinary find could bring between $15 million and $20 million at auction. Only last year, a 25.5-carat fancy blue diamond from the Cullinan mine was sold at auction for $16.9 million.
A smaller fancy blue diamond weighing 5.30 carats broke the world record for price per carat last year when it fetched $9.5 million at Bonhams Fine Jewellery sale in London. The $1.8 million-per-carat bid eclipsed the previous record holder of $1.68 million per carat.
The most famous gem to emerge from the Cullinan mine is the largest gem-quality rough diamond ever found — the "Cullinan Diamond" at 3,106.75 carats. Other magnificent Cullinan-sourced gems include the 545-carat "Golden Jubilee" and the 530-carat "Great Star of Africa." Over its 111-year history, the Cullinan mine has produced more than 750 diamonds weighing more than 100 carats and is considered to be the most important source of blue diamonds in the world.