Botswana’s 2,492-carat diamond is the second-largest ever found. The Cullinan Diamond, discovered in 1905, in Pretoria in modern-day South Africa remains the largest. In its original form it weighed 3,100 carats. Cut into smaller stones, some are prominently featured in the British monarchy's crown jewels. There have been petitions to return them to South Africa, where it was mined.