In 1898 Sir Thomas Cullinan was handed a three carat diamond found along a farm fence. He studied the area and came to the conclusion that the diamond was washed down from a nearby hill. Sir Cullinan made an attempt to buy the land from the owner, Joachim Prinsloo, but did not succeed. After Prinsloo’s death, he was able to purchase the land for ₤52,000 from Prinsloo’s daughter. The Cullinan kimberlite was discovered in 1902 and in 1903 open pit mining commenced. The mine was named the Premier mine.
On 25 June 1905, the famed Cullinan Diamond, the largest in the world at 3,106 carats (621.2 g), was discovered by Frederick George Stanley Wells, surface manager of the Premier Diamond Mining Company. It was bought by the Transvaal government and presented to King Edward VII.
The town of Cullinan owes its existence to the diamond mining in this area, much like Kimberly.