The Cullinan Diamond was discovered in South Africa in 1905. It weighed 3,106.75 carats (approx 621.35g) and was the largest diamond ever to have been found until the discovery of the Golden Jubilee Diamond which was found in the same mine in 1985. Named after the owner of the mine Sir Thomas Cullinan, it was initially cut into three large gemstones and then subsequently into nine plus many smaller ones.
The Cullinan I and II diamonds are both located in the Crown Jewels. The Cullinan I which is the largest clear cut diamond in the world is located in the Sovereign's Sceptre with Cross. The Cullinan II which weighs 317.4 carats (63.48 g) is in the front of the Imperial State Crown below the Black Prince's Ruby which is actually a spinel. The Cullinan II is the second largest diamond cut from the original Cullinan Diamond.