What is left of bronze age copper production and processing is predominantly the slags which were not processed any further and which archaeologists have found at various archaeological sites. It would be of particular interest to establish a correlation between the different types of slag and specific copper ores and stages of the copper production process. It proves rather difficult, however, to deduce the entire set of relevant initial parameters from the final product, the “slag”. The investigative results of three very different types of slag reveal the distribution of slag and that of the source materials quartz, copper ore and iron ore. In the slag areas, different distributions of its constituents olivine, wüstite and vitreous phase (wollastonite) were observed. From element analysis and plottings in the FeO-SiO 2 -CaO phase diagram, some first conclusions may be drawn as to the formation conditions with regard to the different types of slag.