Owing to its vast and rich mineral resources, the Kerman region is regarded as one of the most significant areas for the identification and extraction of metals in Iran. The city of Bam, located in the southeastern part of this province, has long served as a strategic center linking southeastern Iran with Sistan due to its distinctive geological and geomorphological conditions. Archaeological surveys conducted in the central district of Bam County during 2018–2019 aimed to identify ancient mining areas and metallurgical smelting centers. Drawing upon the results of these field investigations, the present study undertakes chemical and mineralogical laboratory analyses of four ceramic nail samples recovered from four areas associated with metallurgical activities. These analyses were carried out to determine the function of the ceramic nails and to investigate the extraction processes involved. The studied samples were examined through petrographic and geochemical analyses using the ICP-OES method across the four identified sites. Petrographic examination of the ceramic nails indicates high firing temperatures during manufacture and reveals a porphyritic texture containing predominantly igneous inclusions as temper materials. The results of the chemical analyses demonstrate that approximately 72% of the chemical composition of these ceramic nails consists of zinc, thereby confirming the intentional extraction of this metal. The existence of sufficient technological knowledge for the oxidation of zinc and the production of Tutia (zinc oxide) at these sites may indicate the emergence of one of the most sophisticated and technologically advanced metallurgical extraction processes in the ancient world. The analytical results obtained from the ceramic nails recovered from several of these sites further suggest that they were specifically employed in the extraction and production of zinc oxide (Tutia).

The Chah Jamal Khoshomang metal smelting sites are located in Yazd Province, in the Kharanaq district east of Ardakan County, approximately 25 km south of Saghand village and 120 km from the city of Yazd. This study aims to identify the smelting technology and the provenance of the ores used at these sites through field investigations, petrographic analysis, and chemical analysis by inductively (ICP-OES) of slag samples collected from two smelting sites. Petrographic results reveal the presence of the silicate minerals pyroxene and fayalite within a glassy matrix, together with metallic phases comprising native copper, copper sulfide minerals (chalcocite and covellite), and the iron-bearing mineral wüstite. The high proportions of silica and iron oxides in the chemical analysis results, together with the presence of CaO and MgO, indicate the use of siliceous and carbonate fluxes to reduce slag viscosity; combined with the observed mineralogical assemblage, this evidence suggests a smelting temperature of approximately 11001200 °C and a reducing, relatively controlled furnace atmosphere. These smelting sites, which were established for copper extraction, also contain lead, zinc, and silver, indicating that the raw ore feeding these furnaces was derived from a polymetallic deposit. Regarding the provenance of this raw material, ancient exploratory tunnels and pits located approximately two kilometers from the sites can be identified as the local source of feedstock for these furnaces. The findings of this study advance our understanding of ancient metal extraction technology in the central Iranian plateau.