*2.4. Analysis of Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX)*

The microstructures and elemental compositions of the bonded *Rhizophora* spp. samples were obtained and studied using a SEM (FEI Quanta FEG-650, Eindhoven, The Netherlands) and EDX at the Centre for Global Archeological Research, Earth Material Characterisation Laboratory, Universiti Sains Malaysia. The samples with the measurement of (5.0 <sup>×</sup> 5.0 <sup>×</sup> 0.5) cm<sup>3</sup> were taped to a specimen holder with two-sided adhesive tape, and coated with gold by a sputter coater (Quorum Q150T S, Quantum Design GmbH, Darmstadt, Germany). The images were taken at a magnification of 4000×. For EDX analysis, the elements were preset to focus only on carbon, nitrogen and oxygen.
