A. Polla

Crystals and phase transitions in protohistoric glass materials

This article reviews the crystalline material present in representative Bronze Age glasses and glassy materials from Northern and Central Italy. Their nature and formation processes are discussed based on textural, crystallographic, and chemical data. Distinction is made between crystals present in the starting raw materials and left unreacted during the glass production process, crystalline phases deliberately or accidentally formed during manufacturing, and crystalline phases added in the last stages of glass working to change the macroscopic properties of the final material. It is argued that in Bronze Age Italy glass production technology was advanced and well mastered so to produce materials having unique characters of colour and workability.

Archaeometric Investigation of Early Iron Age Glasses from Bologna

There is very little evidence of glass objects in the necropolises of the Bologna area during the Villanovan I period (ninth century BC). None of the few existing glass objects have the typical diagnostic typologies, such as the small blue beads on fibulae, which appear late in the period. During the Villanovan II phase (820–770 BC), a new style of rather precious fibulae appears, together with pins carrying glass beads of ever increasing dimensions. A further remarkable variation in the typology of the glass artefacts occurs during the Villanovan III phase (770–680 BC). The beads of this period, commonly inserted on metallic pins with composite head and fibulae with glass coated bows, are rather peculiar of the Bologna area. The decorated beads of this age have different typologies: mostly they show simple- or stratified-eye motifs, and sometimes wave patterns. In the Villanovan III phase, an increasing use of coloured glass is evident: opaque and transparent yellow glass, transparent light blue glass, and colourless glass are found to be progressively more diffused. Variations in the decorations are also attested, such as the eye motif with concentric circles pattern. A specific group of large triangle-shaped beads having spiral glass wires circling around the top represents a category extensively diffused from Northern Europe to the Near East, with a substantial concentration in the Aegean region, which is probably the original production area.