The largest diamond in the world weighed about 3,106 carats in the rough when it was discovered in 1905 in the Premier Mine in Transvaal, South Africa. He was given the name of Sir Thomas Cullinan, who had discovered the mine three years earlier. The colorless stone was bought by the Transvaal government and presented to en1907 reigning British monarch, King Edward VII.
It was cut into 9 large stones and about 100 smaller ones by I.J. Asscher and Company of Amsterdam, famed for their cutting of the Excelsior diamond, which until the discovery of the Cullinan had been the largest known diamond. The stones cut from the Cullinan diamond, all flawless, are now part of the British regalia.