On the Mystery of One Bead

The results of studying a biconical glass bead (14th century) found during excavations by the Institute of Archaeology, Russian Academy of Sciences, at the settlement of Rostislavl (urban district of Kolomna, Moscow oblast) in 2018 are presented. The studied bead specimen differs significantly from all beads traditionally found during excavations in this region. A combination of a complex of imaging methods (X-ray and neutron tomography), large-scale X-ray fluorescence mapping of the distribution of elements, scanning electron microscopy with energy-dispersive X-ray microanalysis, and phase analysis allow us to determine that the bead decoration was formed by several layers of materials of different composition. Quantitative information about the base composition and trace components is obtained by laser ablation inductively coupled plasma mass spectrometry. It is revealed that the bead was made by combining separate layers of the base and decorating material from glasses of two classes, lead silicate and potash lead. Both established glass classes bring it closer to the medieval glasses of Central Europe. In this case, such a combination of the composition and manufacturing technique of similar objects was first found on the territory of Old Russia.