On January 25th 1905 the Largest Diamond was found. On that day in 1905, at the Premier Mine in Pretoria, South Africa, a whopping 3,106 carat diamond was discovered during a routine inspection by the mine's superintendent. It weighed in at 1.33 pounds, yes that's pounds and was christened the "Cullinan" . It was the largest Diamond found to date. WOW ... now that's a ROCK!!!