What is the name of the largest diamond in the world?

The Cullinan

The largest diamond in the world is "The Cullinan." The Cullinan diamond was discovered in South Africa in 1905, and it weighed about 3,106 carats (1.37 pounds or 621.35 grams) in its rough state. The diamond was named after Sir Thomas Cullinan, who owned the mine where it was found. The Cullinan diamond was later cut into several large gemstones, with the largest piece known as "Cullinan I" or the "Great Star of Africa" weighing about 530.2 carats. Cullinan I is the largest clear-cut diamond in the world and is set in the head of the Sovereign's Sceptre with Cross, part of the British Crown Jewels.