Back to black: Analysis of the earliest natron glass found in Italy

Abstract

An assemblage of black-appearing glass objects (predominantly beads) that is dated to the 9th–7th centuries BCE and found in Iron Age contexts of Southern Etruria and Latium (central Italy) was analysed using portable X-ray fluorescence spectrometry, laser ablation – inductively coupled plasma – mass spectrometry and micro-Raman spectroscopy. The analytical approach allowed us to discuss the technology of glass-making in a period of relevant technological changes. It resulted that the glass that reached the Italian peninsula was somewhat different, from a compositional point of view, from both earlier and later periods. The data collected showed that iron – the main colouring agent for these glasses – was obtained from several sources as was silica – the main component of glass. Lime, one of the main constituents of many types of glass, plays a modest role in this assemblage, which places these samples in a special position because of the peculiar batch formula. At least three centres of raw glass production are suggested by the compositional data, but in each case the glass was imported to the Italian peninsula.