The Cullinan diamond

On 26 January 1905, during his morning inspection, mine superintendent Captain Frederick Wells’ eye was caught by a glint of light on the mine wall. Only nine metres from the surface, he thought it was a piece of broken glass, placed there as a practical joke, and so he used a pocket knife to pry it out. It was in fact a 1.5 pound crystal, measuring 21/4 inches wide, 25/8 inches high and 37/8 inches long. Still thinking it of limited value, but in order to check, he sent it for analysis only to discover that it was a perfectly clear and colourless diamond weighing 3,106 carats - twice the size of the largest diamond found in the world at that point.

The diamond was named Cullinan and bought for £150,000 by the Transvaal Government. Legend persists that the stone was only half of its original size as its one smooth side indicates a natural cleaving process having happened in the rock. Transvaal Prime Minister Louis Botha’s proposal to give the Cullinan to King Edward VII was approved by Parliament and accepted by the King in a 66th birthday presentation on 9 November 1907.

Cutting the enormous stone

The Amsterdam firm of I. J. Asscher and Company was awarded the job and the firm’s principal, Joseph Asscher, studied the stone for three months, assessing the optimum facets on which to cut. After deciding the approach, on 10 February 1908, at 2:45 pm, Asscher was ready. His first strike broke the cutter blade, with no damage to the diamond, but his second stroke was perfect and split the stone as planned. It is reported that Mijnheer Asscher promptly fainted with relief. The two stones, weighing 1,977 and 1,040 carats respectively, were then further cleaved into nine major stones, 96 brilliants and carats of unpolished pieces, with a total weight of 1,063 carats – 65 per cent having been lost in the cutting process.

The two main stones, Cullinan I (The Great Star of Africa) and Cullinan II (The Lesser Star of Africa) were given to King Edward VII, who also bought the 11.5 carat ‘sixth Cullinan chip’ for Queen Alexandra. The pear-shaped, 530 carat Great Star of Africa, now resides in the Tower of London and is set in the British Royal Sceptre. The 317 carat Lesser Star of Africa is also in the Tower of London in the centre front band of the Imperial State Crown of Great Britain.