Copper Technology in Ancient South Asia: An Archaeometallurgical Perspective on Processing Traditions and Technological Evolution

Copper is one of the first and most significant metallic substances in the archaeological and metallurgical history of South Asia, indicating a crucial shift in prehistoric material culture from stone to metal technology. This study offers a comprehensive historiographical and archaeometallurgical analysis of copper processing traditions in South Asia, from the Chalcolithic period (about 3000 BCE) to the metallurgical developments of the medieval era. This study reconstructs the technological sequence of ore beneficiation, pyrometallurgical smelting, casting, and post-solidification working practices utilized by ancient South Asian metallurgists, drawing on archaeological, compositional, and microstructural evidence from significant excavation sites, including the Harappan centers of Mohenjo-daro and Harappa, as well as the pre-Harappan Ganeshwar-Jodhpura cultural complex in Rajasthan. Special emphasis is placed on the compositional progression from pure copper artifacts to arsenical copper and tin-bronze collections, including an analysis of the thermodynamic and microstructural implications of these alloying methods. The paper contextualizes South Asian copper technology within a wider cross-cultural framework, critically analyzing technological similarities and differences with contemporary metallurgical practices in Mesopotamia, the Iranian Plateau, and the Nile Valley. Archival and ethnoarchaeological sources are also examined to track the transfer of indigenous processing expertise over historical periods and its impact on regional craft specialization and interregional trade networks. This inquiry reveals the complexity of early South Asian metallurgical practices and enhances the comprehension of the sociotechnical aspects of metal production in preindustrial societies.