The estimated worth of this over sized gem is valued around 12 million pounds. It was discovered in Africa at the Cullinan mine. It's one of the 20 biggest diamonds ever found, and is 507 carats. Apparently when a diamond is this highly valued it get its own special name. Guess how many carats the largest diamond ever discovered had? 3,106 carats, now that's a big boy. This 507 carat diamond is punny in comparison.