Ozdoby wykonane z „tworzyw szklistych” odkryte na cmentarzysku w Świbiu / Ornaments made of “glassy materials” from the cemetery at Świbie

Ozdoby wykonane z „tworzyw szklistych” odkryte na cmentarzysku w Świbiu / Ornaments made of “glassy materials” from the cemetery at Świbie

Approximately 1,700 beads made of “glassy materials” were discovered in the Świbie cemetery (Figs 13.1–13.4; Table 13.1), the vast majority made of “glassy faience” rather than “true glass”. This is the largest collection of Hallstatt period beads from the territory of present-day Poland. The objects in question were found in at least 40 graves (more than 7% of all graves). Some beads formed necklaces adorning the neck of the deceased. Thanks to anthropological analysis, we know that they mostly accompanied deceased of adult age, presumably more often women than men.
The collection of artefacts studied totals 1,676 beads, of which 117 (7%) were made of “true glass”, while 1,559 (93%) were made of “glassy faience” (a material containing numerous inclusions, usually quartz grains; Fig. 13.5); 172 specimens made of the latter material are decorated (with zigzag lines or dots and/or circles; Fig. 13.6) with yellow glass. In total, the analysed objects can be classified into 16 formal groups or subgroups according to the classification in Purowski 2012; 2019 (single specimens did not fit the classification). Small (< 1 cm), undecorated beads, blue in colour, are by far most numerous (Fig. 13.8). Formal analogies to the specimens found in the Świbie cemetery come mainly from Italy and Croatia (Fig. 13.7).
Thirty-six samples of “glassy material” (body and decorative glass) from 22 beads were examined archaeometrically (Figs 13.9 and 13.10; Tables 13.2–13.15). Analyses were performed using two methods: Laser Ablation Inductively Coupled Plasma Mass Spectroscopy (LA-ICP-MS) (Fig. 13.11) and Electron Probe Micro-Analysis (EPMA) (Figs 13.15, 13.16, 13.18–13.20). Determining the contents of MgO and K2O – indicative of the type of the fluxing agent used – made it possible to distinguish two categories among the “true glasses” analysed: high magnesium glass (HMG) and low magnesium glass (LMG) (Fig. 13.13). Low magnesium and medium potassium glass (LMMK) and low magnesium glass of glassy faience (LMGGF) were identified among the “glassy faience” samples (Fig. 13.14).

The glasses forming “glassy faience” (LMMK, LMGGF) and “true glass” (HMG, LMG) differ in both the contents of the main and trace components (Figs 13.21 and 13.22). Different raw materials were used to produce them, and they were added in unequal proportions. LMMK glasses were produced using sand and a difficult-to-identify flux, while LMGGF and LMG glasses were made using sand and mineral soda. HMG was manufactured using a pure source of silica (quartz stones or sand) and halophyte plant ash. “Glassy faience” is typically blue in colour; it was coloured with cobalt compounds. Light green glasses owe their colour primarily to copper compounds, while opaque yellow glasses were coloured with lead and antimony.
“True glass” was produced in the Eastern Mediterranean, while “glassy faience” was made in European workshops (most probably Italian and “Slovenian-Croatian”).

Artefacts made of “glassy faience” and dated to HaC–HaD1 are found in present-day Poland in a limited area encompassing Greater Poland, Silesia, and the adjacent part of western Lesser Poland. They were probably produced in Italy and the Balkans (Slovenia/Croatia), and then brought along what is known as the Amber Route, through the Alpine passes along the Danube and Morava Rivers to the Moravian Gate and further north. It was probably along the same route that beads made of “true glass”, less common in HaC–D1, found their way to south-western Poland. The material from which they were formed (“true glass”), however, was produced in Eastern Mediterranean areas rather than Europe (as was “glassy faience”).