Iron raw materials provide a privileged source of information for the reconstruction of metallurgical techniques and the circulation of iron products. An interdisciplinary approach, combining archaeological and archaeometrical studies of the exemplars known from the French Iron Age, has been undertaken. This enables a new typological classification to be produced that demonstrates a correlation between morphological and structural properties. Through comparison with chronological data, it is possible to propose a reconstruction of the organization of production according to three main periods, which are characterized by the circulation of different qualities of iron and by diverse levels of artisanal specialization.has been developed in the laboratory 'Metallurgy and Culture'(IRAMAT-CNRS-UMR 5060) and has resulted in several Ph.D. theses (Bauvais 2007;Pagès 2008;Leroy 2010). One of these theses concerns, more specifically, the Iron Age (Berranger 2009a).Iron raw materials can present significant morphological and structural variability, depending on the nature of the metal obtained during the smelting process and the result of the treatments used during the bloomsmithing process. The first objective of this work is to characterize their forms and properties at the external (morphology, metrology, aspect of surface) and internal (nature and proportion of impurities, chemical composition) scale, and to compare their characteristics according to their chronological and spatial position. The aim is also to approach the question of their standardization and the spread of metallurgical techniques, as the typology of semi-products is not only correlated with the thermodynamic conditions of formation (in the smelting and refining processes), but also with matters of craftsmanship and workshop traditions. METHODOLOGYThe zone of this study encompasses the current territory of France (Fig. 1), in the hope of producing evidence for possible regional specificities or, on the contrary, a wide homogeneity, which could not be seen as being random at this scale. The survey includes artisanal and non-artisanal contexts. Outside artisanal contexts, the objects are complete and yield information Figure 1 The distribution of the studied sites, by category of raw iron material.Quality and circulation of materials during the Iron Age in France 665

International audienceIn the early days of iron metallurgy in Western Europe, the most widespread type of 'trade iron' (semi-product) was bipyramidal in shape. Although they are frequently found, little is known about how they were manufactured and circulated, or even about their age. An interdisciplinary approach was applied to the Durrenentzen deposit (Haut-Rhin, France), the third-largest in Europe in terms of artefact quantities, in an attempt to reconstruct the technological, social and economic context that caused them to be abandoned. A morphometric study of the 51 iron bars revealed a high degree of homogeneity, despite variations in detail. Four objects were selected for archaeometric studies. Metallographic analyses show internal differences (quality of the material, nature of the alloys and manufacturing techniques). Chemical analyses also showed different provenances. Finally, radiocarbon analyses of the carbon in steel (iron/carbon alloy) linked this deposit to the early Iron Age. This study provided the first benchmark for more general research, significantly changing perceptions of the economics of iron at the beginning of the Iron Age