Preliminary Investigation of Archaeological Mollusc Shell Beads from Ille, Palawan, Philippines

Pauline Basilia1,2*, Pamela Ruth Mateo1, Patricia Panganiban2, Francis Claravall2, Helen Lewis3, and Victor Paz2†

The highly modified (cut) shell bead assemblage from the Ille site, El Nido, Palawan was suggested to indicate the persistence of a local shell bead manufacturing tradition into the “Metal Age” (~2500 BP), despite the increasing presence of imported stone and glass trade beads. This study documents changes in bead morphology and production techniques through a multi-scalar analytical framework integrating standard morphological classification, optical microscopy, scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, portable X-ray fluorescence (pXRF), and radiometric dating. From a total of 7,494 beads, 8% were identified as “micro” beads, defined by perforation diameters of < 5 mm. The three morphological types (regular, long, and flat) all exhibit conical perforations with smooth internal surfaces, consistent with drilling using metal-tipped implements. Microscopic analysis revealed crossed-lamellar microstructures in the regular and long types, with no prismatic microstructures observed, suggesting use of gastropod shells. Elemental analyses identified predominantly organic residues on bead surfaces, indicating the possible use of plant-based resins. Radiometric dating of three samples situates the micro beads between 1315 and 1167 cal. BP. These findings suggest the emergence of a modified manufacturing tradition characterized by reduced bead size and the adoption of metal drill technology, while maintaining earlier (“Neolithic” 5000 BP) material preferences, such as gastropod shells (e.g., Conus sp.) and tree resins as likely appliqués.