ORIGINAL PAPER Egyptian faience glazing by the cementation method part 2: cattle dung ash as a possible source of alkali flux Mehran Matin & Moujan Matin Received: 25 June 2014 /Accepted: 10 November 2014 # Springer-Verlag Berlin Heidelberg 2014 Abstract Based on our current awareness, there are three distinct primary sources of alkali flux in the ancient Egyptian faience making: natron, soda rich plant ash and the so-called ‘mixed alkali fluxes’. Whereas the nature and origin of the first two types are identified to some extent, there are more questions regarding mixed alkali fluxes. In an attempt to provide further clarification on the latter source, a series of replication experiments on the production of Egyptian faience by the cementation glazing method were conducted using cattle dung ash as the source of alkali flux. After firing at 980 °C, the appearance of the faience objects, the microstruc- ture and the chemical composition of selected samples obtain- ed using scanning electron microscopy/energy-dispersive spectroscopy (SEM-EDS) were investigated. The discussion has primarily focused on cattle dung ash as the most, or one of the most, available sources of ash in ancient societies and its possible use as a source of alkali flux in the production of Egyptian faience, at least by the cementation glazing method. Keywords Egyptian faience . Donkey beads . Cattle dung . Qom technique . Cementation glazing . Alkali flux Introduction At the present time, it is generally accepted that there are three primary sources of alkali flux in the production of Egyptian faience objects: natron, soda rich plant ash and the so-called ‘mixed alkali fluxes’ (Tite and Shortland 2008, 38–43, 204–205). It should be noted that the term ‘Egyptian faience’ in this paper does not refer only to ancient faience objects produced in Egypt, but rather siliceous ceramics of the ancient world in general. The term is however used to distinguish this material from later tin-glazed majolica type earthenwares made at Faenza which are generally known as ‘faience’. ‘Natron’, in modern mineralogy, is the mineral name denoting the compound sodium carbonate decahydrate (Na 2 CO 3 .10H 2 O). However, as an archaeological term, it normally refers to the polyphase evaporite deposits that con- sist mainly of the carbonates, bicarbonates, chlorides, and sulphates of sodium. Furthermore, this term may be used specifically for evaporite deposits from the Wadi El-Natrun or Natroun (Arabic for Natron valley, which is the best known source of natron), located in the desert of the northwestern Nile Delta, some 100 km NW of Cairo (roughly 30° 19′–30° 24′ N, 30° 18′–32° 24′ E) (see Shortland 2004; Shortland et al. 2006). Natron consists mainly of sodium carbonate and sodi- um bicarbonate and is characterised by very low potash, lime and magnesia content, typically each being less than 0.5 % (Tite and Shortland 2008, 42). Soda-rich ashes are obtained from burning salt tolerant, halophytic plants of the Chenopodiaceae family, growing in desert regions, coastal and salt marshes (Tite et al. 2006). The chemical composition of plant ash does not merely depend on the plant species but also on factors such as the preparation circumstances of the ash, the parts of the plant burnt to ash (i.e. root, stem, leaf and flower), the age of the plant, the season of sampling and the composition of water and soil. Nevertheless, soda-rich ashes generally contain, in addi- tion to soda, significant amounts of potash, magnesia and lime, and the Na 2 O/K 2 O ratios are usually in the range 2.4–11 (Tite and Shortland 2008, 39). Mixed alkali fluxes can be distinguished by significant potash contents (generally higher than those of soda) and by This paper is dedicated to the late Dr. Hans E. Wulff who conducted pioneering studies on the cementation glazing process. M. Matin : M. Matin (*) Research Laboratory of Shex Porcelain Co., 19th St., Kaveh Ind. Township, Saveh 39141-76314, Iran e-mail: moujan.matin@arch.ox.ac.uk Archaeol Anthropol Sci DOI 10.1007/s12520-014-0218-z