The Cullinan Diamond 3,106.75 carats

The Cullinan diamond, also known as the Star of Africa, is estimated to be worth more than $2 billion. It's the largest rough diamond of gem quality ever found, weighing 3,106.75 carats and measuring 621.35 grams. The diamond was discovered in 1905 at the Premier No.2 mine in Cullinan, South Africa, and named after the mine's owner, Thomas Cullinan