For special purposes only: Ceramic casting moulds from the late Bronze and Early Iron Age metallurgical workshop in Grzybiany (SW Poland)

Ceramic moulds are regarded as highly specialised, refractory tools used in metallurgy, yet their production process still needs clarification. Our research aimed to characterise the stages of operational chains applied in mould manufacture. The evidence comes from the Late Bronze and Early Iron Age lake settlement in Grzybiany in SW Poland, dated to 9/8th-5th century bce. The site provided rich data on tin-bronze metallurgy, chiefly the lost-wax technique, involving hundreds of broken and complete ceramic moulds. Multifaceted petrographic analyses of the sampled objects demonstrated that they were made from locally accessible raw material and processed entirely differently from other ceramics from the site. The paste was tempered with fine-grained sand and an exceptional amount of organic material, plastic enough to wrap wax models. This proportion of organic temper did not occur in regular kitchenware of this period. The moulds were fired under well-controlled conditions and relatively high temperatures (700-950 degrees C). Through this sequence of operations, the Grzybiany community obtained high-quality products designed specifically for metallurgical purposes.