Did copper actually arrive in the Aeolian Islands in the fourth millennium BC? the evidence from a small but iconic fragment of vitreous material thought to be copper slag.

A singular fragment of ‘copper slag’ from Lipari thought until recently to be the key artefactual evidence for the arrival of the copper metallurgy in the Aeolian Islands, Sicily, in the 4th millennium BC has now been reappraised, based on scientific analysis with the Scanning Electron Microscope (SEM-EDS). The results and comparative data sets point to the fragment being vitrified fuel ash (VFA). Preliminary experiments using local plant ash heated to high temperature in a laboratory furnace in the presence of SiO2-rich (but not necessarily quartz-rich) beach sand from the island of Stromboli, resulted in sintering but no fusion; this necessitates the closer scrutiny of the sourcing of the raw materials and heating conditions. However, it is suggested that the process is not associated with any attempt to melt or smelt copper.