The Katanga Cross is a form money made of copper bullion poured into a sand cast in the form of a cross. These crosses were made by the Katanga tribe and circulated in the territory of Katanga, which was a rich area for copper mining. The Katanga Cross was so valuable at the time that a single cross could buy 10 kilos of flour, two crosses purchased a gun, three to five crosses bought a male slave, and five to 10 could buy a female slave.