The Cullinan Diamond was discovered by Frederick on January 26, 1905, during a routine inspection, it was a historical discovery for the diamond world since he came across the world's largest diamond at that time. The Cullinan diamond was named after the mine's owner, Sir Thomas Cullinan.

This Cullinan natural diamond is one of the most expensive diamonds in the world. According to some knowledgeable gemologists, the Cullinan Diamond has the sparkle and luster of a Sancy Diamond. 

This Cullinan Diamond was discovered in South Africa's Cullinan mine in January 1905. At that time, the Cullinan Diamond (3106.75 Carat) was the largest diamond in the world by weight. After learning of its significance, the Cullinan diamond was handed to King Edward VII of the United Kingdom in 1907.

Furthermore, a Cullinan diamond was cut into nine parts, and all of the Cullinan diamond's components are mounted on the British crown. The initial half of the Cullinan diamond weighed 530.2 carats, making it the second most valuable diamond in the world after the Golden Jubilee Diamond.

The diamond is now kept at the Tower of London as part of the British Sovereign's Royal Scepter. The Cullinan II diamond, along with several of the lesser cuts of the original Cullinan diamond, is also preserved in the Tower of London as part of the Crown Jewels.