The Cullinan is a famous diamond discovered in South Africa in 1905. Weighing an impressive 3,106 carats, it is the largest gem-quality diamond ever found. The diamond was named after Sir Thomas Cullinan, the owner of the mine where it was unearthed. After its discovery, the Cullinan was cut into several smaller gems, the most notable being the Cullinan I, also known as the Star of Africa, which weighs 530.2 carats. Today, these diamonds are part of the British Crown Jewels, housed in the Tower of London.