Analysis of glass beads from the “Roten Schmelzzimmer” in Arnstadt and glass tableware from the Grafschaft Schwarzburg-Sondershausen dating from the 17th and 18th century

This study investigates various glass objects from the 17th and 18th centuries in Thuringia to gain insight into their manufacturing techniques. The objects include glass beads from the Roten Schmelzzimmer and diverse glass objects from the Schwarzburg-Sondershausen collection. The analytical methods include optical microscopy, CT, SEM-EDX, LA-ICP-MS and Raman spectroscopy. The glass beads from the Roten Schmelzzimmer were identified as soda-lime- and high-lead-silicate glasses, which were made using highly pure sands and halophytic plant ashes as a fluxing agent. These recipes are characteristic from the Mediterranean region. The beads were coloured in 11 different colours with copper, cobalt, manganese, iron, and were possibly opacified with salt and tartrate. The analysed glass objects from the Schwarzburg collection were made using different recipes based on potash-lime-silicate glass with high amounts of potash and calcium, and calcinated-bone ashes as a white opacifier, characteristic of central Europe