Discovered at the Premier Mine, in July 1986, the Centenary diamond weighed 599.10 carats in the rough. Together with a small select team, master diamond cutter Gabi Tolkowsky took almost three years to complete its transformation into the world's largest, modern-cut, top-color, flawless diamond.

Possessing 247 facets - 164 on the stone and 83 on its girdle - the Centenary diamond weighs 273.85 carats, and is only surpassed in size by the 530.20 carat Great Star of Africa diamond (also known as the Cullinan I diamond) and the 317.40 carat Lesser Star of Africa diamond (also knon as the Cullinan II diamond), both of which are set in the British Crown Jewels.

The Centenary diamond was unveiled at the Tower of London in May, 1991.