Title:	Fragment of ornamental wall painting depicting a garland of buds
Material:	loess plaster base (clay and chopped straw), gypsum primer, mineral pigments
Front side or imprint:	imprint
Dimensions:	13 × 11 cm
Site of discovery:	the large columned hall (the room 15) of the palace of Argishti I at Erebuni
Research laboratory that performed the study:	Laboratory of chemical and technological research of the State Research Institute of Restoration (GosNIIR)

The laboratory of the State Research Institute of Restoration analyzed two samples of the plaster base with the remains of the paint layer from the mural fragment U-404. The first sample is a section of the plaster base with a blue pigment (Fig. 1). Results the element analysis of the first sample (sample No. 15 – hereinafter, the numbering of the samples and the results of their chemical element analysis are used from the report of the senior researchers of the laboratory of chemical and technological research of the State Research Institute of Restoration O. N. Belyaevskaya, L. V. Burenkova, V. I. Gordyushina "The Study of the material of fragments of wall paintings of the VIII century B.C.E. on the cultural heritage site of Erebuni (Urartu)" 2018) showed that it consists of Cu-containing pigment, calcite, silicates and iron hydroxides (Table 1).

The remains of the paint layer are represented by a Cu-containing pigment – Egyptian blue (the original ancient pigment). The surface of the fragment is tinted by the restorer’s blue paint, which by its chemical composition belongs to the artificial ultramarine. This blue phthalocyanine pigment was first obtained in 1937, and it was produced as oil paint in the USSR since 1966-1967. Traces of zinc whitewash, the mid-19th century pigment, were also found. All of these late pigments in the first sample indicate restoration works carried out shortly after the discovery of this fragment.

Table 1. The chemical composition of the sample of the paint layer of the mural fragment U-404, sample No. 15.

Oxides	SiO2	SO2	K2	CaO	TiO2	MnO	Fe2O3	CuO	ZnO	BaO
1	2	3	4	5	6	7	8	9	10	11
Composition, mass. %	22,10	2,82	2,50	45,0	0.90	-	13,80	12,55	0,21	0,08

The element analysis of the second sample of the plaster base with the remains of black pigment (sample No. 16) has produced following results (Fig. 2): calcite, gypsum (in almost equal proportions), aluminosilicates and Fe- containing pigment (Table 2).

Table 2. The chemical composition of the sample of the paint layer of the mural fragment U-404, sample No. 16.

Oxides	Al2O3	SiO2	P2O5	SO2	Cl	K2O	CuO	TiO2	MnO	Fe2O3	CoO	CuO
1	2	3	4	5	6	7	8	9	10	11	12	13
Composition, mass. %	2,89	15,42	0,47	13,69	1,63	3,46	37,64	1,61	0,36	21,90	0,30	0,28
Oxides	ZnO	BaO
14	15	16
Composition, mass. %	0,15	0,21

As in most of the other studied wall paintings from Erebuni, the plaster base of the mural fragment U-404 consists of loess deposits with a plant filler in the form of chopped straw.