A Metallurgical Expedition through the Persian Desert

An archaeological and metallurgical investigation was made in the Central Persian desert where diversified mineral deposits occur, the most prominent being gold, lead-silver, copper, iron, antimony, zinc, nickel and chromite. Evidence of heating copper in crucibles in the 5th millenium B.C. Has been found at Tal-i-Iblis in Kerman (the ancient Carmania) province, which also yields old mines and slag heaps. The more easily available cerussite (PbCO 3 ) was used as lead ore before the more deeply located and less readily smelted galena (PbS). The lead mines were a source of Pb and Ag in ancient times and some are mined today for Zn, which was formerly considered an impurity. Fumes of zinc oxide as by-product of lend smelting furnaces in this area were mentioned by Marco Polo who used the early name tutiya. The hypothesis that the use of iron ore in smelting lead was a factor in the discovery of iron still has not been proved. The copper-stained crucibles found at Iblis were probably used for casting rather than smelting; the crucible melted in an experiment in which a temperature of more than 1200°C was reached over a charcoal fire in forming a copper bead.