Ancient procedures of gold cementation and gold scorification: considerations on their reliability through experimental archaeology, interpretation of chemical reactions and thermodynamics

Reproductions of ancient gold-silver parting procedures were carried out following experimental archaeology protocols and interpreted in the light of the analytical characterization of reagents and products, aimed to define the chemical reactions involved, in order to prepare and execute the thermodynamic validation of them. Analyses were conducted by the authors on different kinds of ancient recipes, coming from textual evidence of a wide chronological range, involving the use of different cementation components. Initial archaeological experiments were conducted using a cement based on a recipe of Pedanius Dioscorides (I century AD) for the production of ios scolekos. Aferwards, the use of brick powder and salt, a procedure described for example in Teophilus, was reproduced and interpreted through the identification of reagents and products involved in the pyrometallurgical processes. A new set of experiments was then designed and carried out with cements containing the natural weathered mineral complex called “misy”, following descriptions given by Galen (II century AD), Dioscorides and Georgius Agricola (XVI century). Other experiments reproduced the description o gold separation and collection made by Agatharchides of Cnidus (II century BC), afer his direct observations made in the Nubian gold mines. Te aims of these studies are to enlighten and classiy the technical processes, to evaluate the reliability and the parameters of the procedures (e.g. temperature, atmosphere, and duration) and the characterization of products: this information contributes to new insights in the study of the ancient production of gold and precious metal artefacts.