Cullinan Diamond

The Cullinan Diamond is the largest gem-quality rough diamond ever found, weighing 3,106 carats when discovered at the Premier No. 2 mine at Cullinan, South Africa, on 26 January 1905. Surface manager Frederick Wells found the near colorless stone, which was named after Thomas Cullinan, the mine's owner. Its two largest cut stones, Cullinan I and Cullinan II, are set in the British coronation regalia and displayed in the Jewel House at the Tower of London.

The Transvaal Colony government bought the rough diamond in 1907 for 150,000 pounds and presented it to King Edward VII at Sandringham House on 9 November 1907, his 66th birthday. Joseph Asscher and Company of Amsterdam began cutting the stone on 10 February 1908, an eight month process that produced nine major stones totaling 1,055.89 carats plus 96 minor brilliants.

Cullinan I, the Great Star of Africa, weighs 530.2 carats and is set at the top of the Sovereign's Sceptre with Cross. It is the largest cut clear diamond in the world. Cullinan II, the Second Star of Africa, weighs 317.4 carats and is set in the front of the Imperial State Crown, below the Black Prince's Ruby. Both belong to the British monarch in right of the Crown.