Scientific Study of Iron Age Gem Bead from Thailand

In this paper, X-ray fluorescence spectroscopy (XRF), laser Raman spectroscopy(LRS), optical microscopy (OM), combined with silicone resin molding method were used to analyze some gem beads dated to Iron Age, which were unearthed in Khao Sam Kaeo site in Thailand or collected from Thailand and Myanmar. The mineral phases of both beads and inclusions that contained in some bead matrix, processing techniques of the beads and their provenance were studied based on scientific analysis. The results of XRF and LRS showed that the main mineral phases of the gem beads include beryl (aquamarine), almandine, crystal and chalcedony. According to the features of micro-marks obtained, there are two kinds of techniques that were used to grind the beads. One is the rotary grinding-stone technique, the other is the leather bag technique. Perforations of the beads, which has four combination patterns, are drilled from single-side or double-side. The micro-mark characteristics of drilling process show that the drilling tools include diamond drills, stone drills, rod-shaped drills and so on. The results of scientific analysis show that the gem beads have a variety of material properties, perforation characteristics and processing techniques, which shows the provenances of these gem beads are multi-origins, and some beads are closely related to South Asia.