The Mystery of Glass Beads

In the past few decades, numerous archeological sites in Taiwan have unearthed a large number of glass bead artifacts. These sites are scattered along the coast and in the mountains. The earliest known glass bead artifacts date back nearly two thousand years. The "Old Xianglan Archeological Site" in Taitung County's Taimali Township has been continuously excavated since the end of 2003, yielding thousands of finished glass beads, dozens of glass waste, and artifacts related to metal processing.

To understand the stories behind these glass beads, we examined the surface patterns and bubbles of the glass beads under an optical microscope. The majority of the beads from the "Old Xianglan Archeological Site" show parallel lines to the hole orientation on their surfaces and cross-sections, indicating that they were made using the "drawing method." Their appearance also matches the typical characteristics of "Indo-Pacific beads."

But among these glass materials, some solid glass strips were wound around metal rods. This shows they were made using the "Winding Method." This suggests that the local glass bead crafting in "Old Xianglan" back then used the winding method, not the drawing method. From this, we think the drawn beads found in "Old Xianglan" may have been traded with other places and then brought to "Old Xianglan."

Archeologists use scientific techniques to analyze glass beads from multiple angles. In addition to examining the manufacturing process using an optical microscope, they also use a scanning electron microscope combined with energy-dispersive spectroscopy (SEM-EDS) to understand the composition at the microscopic scale. This helps to infer the production formula and source of the glass beads. For example, yellow glass beads excavated from the "Chiwulan Archeological Site" derive their yellow color from lead tin crystal, with surrounding glass containing plant ash, reflecting traditional characteristics from West Asia. After comparing information obtained through scientific techniques, these colorful glass beads gradually connect the links between Southeast Asia, South Asia, and West Asia during the Metal Age around 2000 years ago.