Technological and compositional variation in pink and white pastes from a coffin set of the late Third Intermediate Period (Thebes, ca. 680–664 BCE)

Abstract

Ancient Egyptian artefacts often feature an intriguing assortment of plaster-like materials. These range from authentic plasters, derived from heated lime and gypsum, to mud, calcium carbonate and calcium sulphate-based pastes bound with organic media and sometimes integrated with clay minerals and plant fibres. Although architectural plaster use in ancient Egypt has received some attention, a gap remains in the analysis and precise characterisation of the materials applied to objects. Understanding their composition can shed light on technological changes, provide contextual insights and support provenance studies. A minimally invasive approach was applied to the two coffins of Pakepu (intermediate and inner), a funerary ensemble from Thebes dating back to about 680–664 BCE, and to a group of coffin fragments from the same area and period, employed as a comparison group. The inner coffin of Pakepu and the fragments all exhibit a complex surface layering reminiscent of cartonnage. This is in contrast to the much simpler surface construction seen on the intermediate coffin. Optical microscopy, scanning electron microscopy with energy dispersive spectroscopy and Fourier transform infrared spectroscopy were employed to characterise the inorganic constituents. Ground, unheated calcite was detected in all the pastes, but differences in micromorphology and the distribution of minor elements (particularly Mg and Fe) in the Pakepu inner and intermediate coffin, and in the fragments, point to the involvement of different workshops, geological sources and manufacturing protocols in the production of these materials. (For a summary in Arabic, see Online Resource)