The magnificent Cullinan Diamond – the largest diamond ever found- is incorporated into the Crown Jewels.

The stone was discovered near Pretoria in modern -day South Africa in 1905, and is named after the chairman of the mining company, Thomas Cullinan. In its uncut state, it weighed 3,106 metric carats and boasted a size of 10.1 x 6.35 x 5.9 cm. This scale, coupled with its extraordinary blue-white colour and exceptional clarity, made it the most celebrated diamond in the world. 

Cutting this extraordinary diamond was a considerable challenge.  The stone was dispatched to the leading diamond cutters of the day, Asschers of Amsterdam. It took four days to prepare the groove for the cleaving knife, and the very first blow broke the knife rather than the diamond. Over the next eight months, three men worked for 14 hours a day to cut and polish nine large stones from the original diamond. Each of these stones was given a number from I to IX, and today they are still referred to in this way. 97 small brilliants and some unpolished fragments were also created.

After King Edward's death in 1910, King George V had Cullinan I and II set in the Sovereign's Sceptre and Imperial State Crown respectively. Both these stones are still in the regalia today. The remaining numbered diamonds were kept by Asschers as payment for their work. Cullinan VI and VIII were later brought privately by King Edward VII as a gift for Queen Alexandra, and the others were acquired by the South African Government and given to Queen Mary in 1910, in memory of the Inauguration of the Union. They were bequeathed to Queen Elizabeth II in 1953.

Click on the objects below to read more about how Cullinan I and II were incorporated into the Crown Jewels. Stones III-IX today form part of Queen Elizabeth II's personal jewellery and are not shown here.