Archaeometrical Investigation of Sicilian Early Byzantine Glass: Chemical and Spectroscopic Data*

Abstract

A series of early Byzantine glasses, recovered in Ganzirri (Sicily, Italy), was analysed for major, minor and trace elements. All the analysed fragments were found to be natron‐based silica–lime glass. Concerning minor and trace elements, the samples can be divided into two groups: glass with high Fe, Ti and Mn contents (HIMT glass) and glass with low levels of Fe, Ti and Mn. These results, strictly in agreement with literature data for glass of the Mediterranean region, can be interpreted as a consequence of the wide trade network established in this region and of the intense circulation of raw glass and artefacts from different Mediterranean areas. X‐ray absorption spectroscopy studies at Fe and Mn K‐edges, performed on HIMT glass, indicate that Fe is in the oxidized form while Mn is in the reduced form.

A XANES study of chromophores in archaeological glass

“…-The plot was corrected, the number of samples is 15 Table 1: For not to be mistaken between "not determined" and "not detected", please define "n.d." -A new table (1) with the whole chemical data was added. The explanation of the abbreviation is given in the caption, Reviewer #2: The content and layout of the manuscript are in line with previous papers published by the two first Authors in Archaeometry-focused Journals -namely, references [3][4][5][6], [15,16], [22]. Beyond a few specific suggestions that follow, a more detailed physical discussion of XANES data is recommended for a publication in Applied Physics A.…”

“…4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23]. XANES spectroscopy has also been successfully applied to the speciation of Mn in minerals and glass [e.g.…”

“…In particular, XANES studies of Mn in ancient glass were performed to understand whether this element was present as an impurity in the raw materials or intentionally added to the batch as a decoloring agent (e.g. [6,16,23]. It is, in fact, well known that in ancient times Mn was added as pyrolusite to the batch to control the final color of the glassby means of a redox reaction in which Mn 4+ reduces while Fe 2+ oxidizes -neutralizing the effect of Fe 2+ contained in the heavy minerals present as impurities in the sand, and imparting the typical yellow-green color to the artifacts.…”

Composition and production of late antique glass bowls type Helle

“…From the 4th century AD, this compositional group is found across the entire Roman Empire (Nenna, 2014), from Carthage (Freestone, 1994), Cyprus (Freestone et al, 2002) and Egypt (Rosenow and Rehren, 2014) via Bulgaria (Rehren and Cholakova, 2010), Italy (Mirti et al, 1993: Group E;Arletti et al, 2010) and France (Foy et al, 2003: groupe 1) up to Britain (Foster and Jackson, 2009). Diagnostic for this group are also higher concentrations of chromium, vanadium and zirconium compared to most other main compositional glass groups (Aerts et al, 2003).…”

Evidence of early medieval soda ash glass in the archaeological site of San Genesio (Tuscany)

“…4 we can appreciate how the distribution of the CaO and Al 2 O 3 contents of the S. Genesio glass appears to be centered on the HIMT compositional area, with a certain spread. It is interesting to point out that in the site of Ganzirri (Sicily), glass of similar age has a quite different composition, with most of the samples with a "Levantine I" composition (Arletti et al, 2010). The spread of the values outside the HIMT area can be explained, as mentioned by Freestone et al (2002a, b), by the increasing variability (going along with time) of the cullet (recycled glass) employed in glassmaking, thus resulting in a dilution/averaging out the original compositions.…”