An archaeometric investigation of glass beads decorating the reliquary of Saint Simètre from Lierneux, Belgium

Abstract

The reliquary of Saint Simètre (or Symètre), which is exposed in the Saint André church of Lierneux, was produced during the middle of the 13th century. It is made of a wooden chest with a roof (77 × 28 × 39 cm) covered by silver and golden copper, and decorated by 39 stones which were analysed by Raman and pXRF techniques to determine the nature of colouring agents and of raw materials. The results confirm the identification of 39 glass beads with green, blue, red or pink colours and showing a simple cutting. They show a lead silicate composition (45–55 wt% PbO) with a high level of potassium (5–10 wt% K2O), and iron, cobalt, manganese and/or copper as coloring agents. The silver samples contain 98 wt% of Ag, and the golden border contains approximately 85 wt% of Cu and 14 wt% of Au. The brass decorations on the roof shows an average of 68 wt% of Cu and of 29 wt% of Zn. This study confirms that lead glass beads are contemporary to the reliquary and imported from central Europe.