Transmission electron microscopy (TEM) applied to ancient pottery

A comparative study of ancient pottery has been carried out, which utilized X‐ray diffraction, optics and scanning and transmission electron microscopy (SEM and TEM). Samples came from three prehistoric sites in northern Spain (La Rioja). Transmission electron microscope techniques, which use intact ion‐milled samples, allow minerals and glass to be imaged in situ, providing data on textures, crystal structures and composition. TEM provided detailed characterization of both source‐characteristic raw materials and products of the firing process, and revealed the range of intermediate phases, most of which had sizes beyond that of resolution by SEM. More importantly, TEM provided definition of the reaction processes, from starting materials through glass and new crystalline phases, providing data on both temperature and duration of firing.