Chemical and mineralogical investigations of majolicas (16th–19th centuries) from Laterza, southern Italy

Abstract

Abstract Laterza (southern Italy) was the most important town for the manufacture of Apulian majolica ceramic from the 16th century until the end of the 18th century. The Laterza majolicas have previously been subjected to only preliminary analyses. This study extends the archaeometric knowledge of the Laterza productions with mineralogical, petrographical and chemical characterizations of ceramic body, glazed coating and pigments of the majolica. A number of 16th to 19th century pottery and tile fragments of majolica have been studied and compared with clay from local and surrounding deposits. Analyses were carried out by optical microscope, scanning electron microscope, energy-dispersive spectrometry, X-ray powder diffraction, X-ray fluorescence and inductively coupled plasma. A purification process of the raw material is suggested and for some fragments, doubtfully attributed to Laterza, a different place of manufacture. Slip (‘ingobbio’) was never found under the glaze. Si, Pb and Sn are confirmed as the principal elements in the tin-glazed coatings. The differences in the glaze opacity were attributed to different manufacturing techniques and not simply the quantity of tin. The orange-yellow colour is due to a Sb-Pb compound; black to Ni with a lower amount of Co, Fe and Sb; blue to Co, As, Fe and Ni; and Mn is the pigment of the violet-brown.