A 3000-Year-Old Copper Smelting Site Sheds Light on the Origins of Iron Overview Research from Cranfield University reexamines a 3000-year-old copper smelting site in southern Georgia called Kvemo Bolnisi, offering fresh insights into the transition from the Bronze Age to the Iron Age. The study reveals that copper smelters at this site used iron oxide mineral hematite as a flux in copper production, rather than smelting iron itself. This finding supports the theory that experimentation with iron-bearing materials by copper smelters was a foundational step toward the invention of iron metallurgy. --- Key Findings Site and Historical Context Kvemo Bolnisi is a 3000-year-old smelting workshop originally excavated in the 1950s. The site contained piles of hematite (iron oxide) and slag, initially thought to indicate early iron smelting. New Analysis The research reinterprets the hematite role: it was used as a flux to enhance copper extraction, not for iron smelting. This indicates early metallurgists intentionally experimented with iron-bearing minerals as part of copper production. Implications for Iron Invention The findings bolster a longstanding hypothesis that copper smelters' experiments with iron compounds paved the way for iron smelting technology. Understanding the use of iron oxide in copper smelting illuminates a critical evolutionary phase in metallurgy. --- Importance of Iron and the Iron Age Prior to iron smelting, iron was rare and sourced from meteorites (meteoric iron), making it more valuable than gold. Extracting iron from ore through smelting revolutionized material use, leading to tools, weapons, and infrastructure development. The onset of the Iron Age spanned centuries and eventually supported empires like Assyria and Rome, plus modern industrial frameworks. --- Scientific Approach and Tools Researchers used modern analytical tools including scanning electron microscopy to study slag and mineral samples. These advanced techniques allowed deep chemical and microstructural insights into ancient metallurgical processes. --- Quotes from Researchers Dr. Nathaniel Erb-Satullo, Visiting Fellow in Archaeological Science at Cranfield University, emphasized: "This site shows intentional use of iron oxide in copper smelting, reflecting early recognition and experimentation with iron-bearing materials. Such experimentation was crucial to iron metallurgy's development." --- Publication and Additional Resources The work is published in the Journal of Archaeological Science (2025): DOI: 10.1016/j.jas.2025.106338 The research highlights the intersection of archaeology, geology, and materials science to understand ancient technologies. --- Related Topics and Further Reading Meteoric iron in early Iron Age artifacts in Poland. Anemia and health concerns linked to iron deficiency. Studies of ancient metallurgy and early iron use. --- Summary This research revises previous interpretations of the Kvemo Bolnisi site, clarifying that copper smelters used iron oxide as a flux rather than for iron extraction. By demonstrating how ancient metallurgists manipulated iron-bearing minerals, the study offers critical evidence on how the Iron Age likely emerged through incremental innovation built on earlier copper technologies. --- Provided by Cranfield University; edited by Robert Egan.