Naturwissenschaften und Technologie in der Kunst; Akademie der bildenden Künste Wien; Schillerplatz 3; 1010 Wien
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Glass of Ephesos - Scientific Investigations on Glass Findings from Hanghaus 1

The samples investigated can be divided into 2 groups. The first group includes samples from Hanghaus 1, a residential area in ancient periods, the second group of samples were excavated at the Agora of Ephesos (chamber J and L). At these chambers also residuals of ancient glass ovens could be found indicating that there had been a glass workshop.

All samples could be analyzed using energy dispersive micro x-ray fluorescence analysis (µ-XRF) and energy dispersive microanalysis in a scanning electron microscope (SEM/EDX). With the knowledge of the chemical composition of these samples the following problems should be considered:

  1. classification and characterization of the glasses
  2. comparison of the samples originating from the Agora with those originating from Hanghaus 1 to proof a local production
  3. determination of the provenance of the glasses

For the quantitative analysis a µ-XRF instrument built within a project of the EU (Project No. SMT4-CT98-2237) was used. The measurements with the µ-XRF system were carried out in air and therefore some x-ray lines (E < approximately 3.7 keV) can not be detected. Consequently, elements such as Na, Al or Mg, which can be the main constituents of a silicate glass, had to be analyzed using SEM/EDX. For the complete determination of the chemical composition of the glass fragments and to avoid errors due to the measurement setup the results of the µ-XRF analysis had to be combined with SEM/EDX and were normalized.

Furthermore, the results of the analyses could be evaluated using two statistical methods:

  1. the creation of scattering plots correlating the concentrations of the element oxides
  2. performing a principal component analysis

Starting point for the classification of the glasses was the subdivision of the analyzed glasses in 19 groups based on typological characteristics of the objects. The interpretation of the statistical evaluation showed homogenous compositions of some glasses, which enabled the creation of 12 new glass groups. The comparison of these groups with the literature showed that some of these groups can be associated with the levantine I group, others with the so- called HIMT glasses. But not all glass groups could be classified in this way.

Comparing the glass samples from the Agora with those from Hanghaus 1 an inhomogeneity of this group can be observed, but no separation into subclusters is possible. This circumstance leads to the assumption that the glass workshop in Ephesos was based on recycling of glass.

On some of the analyzed glasses also LA-ICP MS was performed, to achieve a differentiation of the investigated samples due to the obtained 207Pb / 206Pb and 208Pb / 206Pb isotope ratios. The investigated glass samples from Ephesos can be separated in different groups which vary significantly by their Pb isotope ratio pattern. The separation of the 10 samples of Hanghaus I is in good accordance with the glass groups defined from the XRF and SEM/EDX analyses, taking into account the small number of investigated samples. The clustering of the 5 investigated samples from the Agora (3 raw glass samples, 2 glassware) is much more significant than from the XRF and SEM/EDX analyses but does not correspond with the separation into raw- and shaped glass.

In general, the classification of ancient glasses, especially considering primary workshops, is very difficult, because only a few data are available. Additionally, considering the big effort the primary production of glass made, glass had been a very valuable material and therefore recycling was very popular, as could be shown with the glass samples of Ephesos.

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