The tin content of the blue-glazed Hutterite and Haban ceramics - Implications for the production technology based on results of the handheld XRF and EMPA analyses

The Hutterites and Habans produced coloured-glazed, mostly blue- and yellow-coloured vessels alongside their white-glazed faience ware. However, the production technology of the coloured-glazed vessels, specifically the nature of the glaze, is matter of debate among scholars. Both coloured tin glaze and coloured engobe covered by a transparent lead laze were supposed to have been applied on the ceramics. Circa 140 objects of blue-glazed Hutterite and Haban museum objects and archaeological artefacts were analysed by a handheld XRF spectrometer. In addition small fragments of selected ceramics were studied by electron microprobe analysis (EMPA). According to the XRF measurements the blue glaze of all the studied Hutterite and Haban ceramics contains tin in variable amounts (from about 0.015 wt% up to 13 wt%). The EMPA technique showed that tin in the form of tin oxide opacifier was deliberately added to the single-layered alkali-lead or lead-alkali glaze. These data confirm that the tin glaze technique was used during production of blueglazed ceramics, and in this aspect they can be regarded as faience. The blue glaze of the Haban vessels produced by “mining town workshop” contains tin in very low concentrations (Sn