Toward a fast non-destructive identification of pottery: The sourcing of 14th–16th century Vietnamese and Chinese ceramic shards

Vietnamese pottery appears to have been exported by the Indian Ocean Monsoon trade since medieval times. However, the number of identified Vietnamese stoneware/porcelain remains very small by comparison with Chinese productions (< 0.1%) and the question of mis-assignment remains open. In order to evaluate the potential of on-site identification, an assemblage of 13 ceramic shards recently excavated from the medieval port site of Qalhāt (Omani coast) assigned to Vietnamese and/or southern Chinese productions by using stylistic/visual criteria has been qualitatively analysed with a portable X-ray fluorescence instrument and a transportable Raman spectrometer and compared with data recorded on a large variety of reference shards excavated from different kiln places of the Hong River bank, Central Viet Nam, and from the Cù Lao Chàm shipwreck. In the glaze/body, the zirconium, rubidium and titanium contents allow distinguishing between Vietnamese and Chinese ancient/modern productions. The potassium vs. calcium glaze content is also very efficient for the differentiation between the Chinese and Vietnamese origins. Measurements confirm ∼80% of the assignments based on eyes examination. The manganese, Rare Earth and cobalt content also contribute to identify the production places. Comparison of the glaze sections and chemometrics are used for a final comparison of the production technology: slip, overglaze or underglaze décor, etc.