Evidence of Local Glazing and Firing Techniques in Glazed Ceramics from Dinajpur Bangladesh

This study presents a comprehensive archaeometric investigation of medieval glazed ceramics—commonly termed 'Index Pottery'—from the Dinajpur region of northwestern Bangladesh, aiming to uncover local production techniques and technological diversity. Using X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), five glazed pottery samples from four archaeological sites were analyzed to determine their mineralogical and microstructural composition. The mineralogical analysis revealed quartz (41.1%-71.4%) and muscovite (18.3%–47.3%) as dominant phases, with minor components such as zoisite (0.4%–14%), apatite (1.9%–4.1%), and nepheline (present in two samples). Elemental analysis confirmed high concentrations of oxygen (45.75%–64.56%) and silicon (31.01%–33.54%), along with variable amounts of aluminum and sodium, the latter indicating differential use of fluxes in glaze preparation. Notably, sodium-based fluxes were present in samples fired at lower temperatures (~950–1100 °C), while sodium-absent glazes likely required higher firing ranges (~1100–1250 °C). The presence of muscovite implies intentional enhancement of thermal resistance, while zoisite and apatite may have contributed to glaze stability and coloration. These findings suggest that local artisans employed a range of glaze formulations and firing strategies, reflecting both technical competence and adaptive experimentation.