Petra Diamonds Limited engages in the mining, processing, sorting, and sale of rough diamonds in South Africa and Tanzania. It holds interests in three underground producing mines, including the Cullinan, Finsch, and Koffiefontein mines located in South Africa; and the Williamson mine located in Tanzania. The company also provides treasury, beneficiation, and other services. Petra Diamonds Limited was incorporated in 1997 and is based in London, the United Kingdom.