A 29.6 carat Natural Blue Diamond Found at Cullunan Mine

By: Gino Di Geso

LONDON: A 29.6 carat blue diamond, one of the rarest and exciting  has been discovered at a South African mine by Petra Diamonds. The miner said the “exceptional” acorn-sized diamond, small enough to fit into the palm of a hand, was unearthed at the Cullinan mine near Pretoria.

The mine, owned by the firm since 2008, was also where the Cullinan Diamond was found in 1905 — described as the largest rough gem diamond ever recovered and weighing 3,106 carats. Other notable diamonds found in the mine include a 25.5 carat Cullinan blue diamond, found in 2013 and sold for $16.9 million, and a diamond found in 2008, known as the Star of Josephine, which was sold for $9.49 million.

The vast majority of Blue Diamonds owe their color to the presence of Boron. The bonding of Boron to Carbon causes absorption in red, yellow and green parts of the spectrum producing blue color. Blue Diamonds may contain Grey , Violet and Greenish modifying color.

“An amazing find. The Cullinan mine (formerly Premier mine) continues to be the only consistent source of natural color type IIb diamonds in the world.” - Thomas Gelb, NCDIA Educational Director

In my opinion, this piece of blue diamond rough, based on its projected color yield, is the birth of a stone for the history books. The winning bid, based on potential yield and clarity could easily break the world record for price per carat for a rough diamond. - Alan Bronstein – NCDIA VP (Aurora Gems)

Petra Diamonds is due to release figures on production and sales for the six months to Dec. 31 on Thursday, but these will not take into account the find which occurred in January.

The mine, owned by the firm since 2008, was also where the Cullinan Diamond was found in 1905 — described as the largest rough gem diamond ever recovered and weighing 3,106 carats.
Other notable diamonds found in the mine include a 25.5 carat Cullinan blue diamond, found in 2013 and sold for $16.9 million

Source: (Reuters)