Comparative Analysis of the Modern and Ancient Coloring Pigment in the Paintings from the Two-Eyed Stone (Dvuglazyi Kamen’) Pictograph (the Neyva River, the Middle Urals)

Abstract

The results of a comparative analysis of the ancient paint layer of the Two-Eyed Stone (Dvuglazyi Kamen') pictograph (Alapaevsk, the Neyva River) and the experimental painting made at the same place in 1992 using paint prepared in accordance with the supposed ancient technology (grinding a piece of local iron ore with lard) are presented. The studies of mineral and chemical composition are carried out by SEM-EDS and Raman spectroscopy. The results do not preclude the use of local raw materials (hematite from iron ore occurrences of the "Alapaevsk" type) as a coloring pigment by ancient people. The technology of manual grinding of hematite-containing material, both in ancient times and today, has made it possible to obtain a finely dispersed pigment with almost submicron particle sizes. The ancient paint layer is covered with secondary formations, represented by crusts consisting of gypsum and weddellite crystals, in some cases with thin dolomite-magnesite interlayers on gypsum. Possible mechanisms for the gypsum crust formation are proposed. The formation of oxalate crusts (weddellite) may result from biological activity of lichens, whose probable traces are detected in the experimental painting. The traces of fat from domesticated ruminants, most likely ram, which could be added as a binder, in contrast to the experimental paint based on pig fat, were found in the organic component of the ancient paint. Both paint samples contain an admixture of organic substance of plant origin derived from the environment.