Humble fragments of clay crucibles and coin molds flecked with gold excavated by a joint team of British and Malian archaeologists in 2005 led archaeologist Sam Nixon, in consultation with Thilo Rehren, a specialist on ancient materials and technologies, to theorize how West Africans used them to purify gold and cast unmarked coins during the 10th and 11th centuries in Tadmekka, Mali. The theory was supported by writings from that time—largely thought in recent times to be exaggerated—that praised Tadmekka's pure gold "blank dinar" [coins].
* This article was originally published here
