The Cullinan mine is known to be the third richest diamond mine in the country producing high quality gem diamonds. The Cullinan kimberlite pipe was discovered 1902 and open pit mining started in 1903. The diamond was renamed 'Cullinan' as part of its centenary celebrations and to link the mine to the heritage of the Cullinan diamond, which provided the two main polished diamonds within the British Crown. It is reported that the 2 big diamonds on the British crown were extracted from the Cullinan mines.