The story of a soil that became a glaze: Chemical and microscopic fingerprints on the Attic vases

Abstract

In order to study the provenance of the clays used for the black-glaze (BG) decoration of Athenian pottery, we analysed in situ with the use of a Bruker handheld-PXRF system ~100Geometric, Archaic and Classical decorated sherds from the 19th century excavations at the Acropolis of Athens (Graef and Langlotz, 1933), Boeotian ware from the Kavirion excavations and test pieces from the early excavations at the potter's quarter in Corinth. The sherds were also examined microscopically and documented by means of optical microscopy/digital photography. The results were compared with laboratory BG specimens produced by following the “iron reduction technique” at the THETIS workshop in Athens. The laboratory BG specimens used clay-colloids from 36 different ferruginous, illitic, low-calcium content, clay-sources in Attica. Trace element comparison between modern and ancient BG samples, with respect to the Zn content, points to the occasional use in antiquity of clay-deposits from Laurium. In addition, two phenomenological features of the ancient BG samples also present in prominent museum exhibits, i.e. the characteristic star-like micro-cracks and distinct brown-black colour shades, appear in the laboratory BG specimens produced from specific clay-deposits in the Panakton plateau and Mount-Parnes region.