Title:	Fragment of wall painting depicting a lower part of a male figure
Material:	loess plaster base (clay and chopped straw), gypsum primer, mineral pigments
Front side or imprint:	imprint
Dimensions:	15.5 × 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)

Two samples of the plaster base with the remains of the paint layer were taken from the mural fragment U-405 in the laboratory of chemical and technological research. For a more detailed study of the composition in each sample, two different sites were identified for chemical analysis. The element analysis of the first sample (Fig. 1) of the plaster base (sample No. 9/1) yielded the following results: calcite, gypsum (the ratio of calcite and gypsum – 2.2:1), quartz, aluminosilicates, iron hydroxides (Table 1A). The content of calcite and gypsum is unevenly distributed in the mass of plaster. Analysis of the chemical composition of the second section of sample No. 9/2 showed the presence of calcite, quartz, aluminosilicates and iron hydroxides (Table 1B).

Table 1. The chemical composition of the sample of the plaster base of the mural fragment U-405, sample No. 9/1-2.

Oxides	МgO	Al2O3	SiO2	SO2	K2O	CaO	TiO2	Cr2O3	MnO	Fe2O3	BaO
1	2	3	4	5	6	7	8	9	10	11	12
A. 9/1 Composition, mass.%	1,93	10,60	37,70	6,02	4,17	25,46	1,16	0,215	0,19	12,47	0,07
B. 9/2 Composition, mass.%	3,63	11,25	42,78	-	3,31	7,52	0,82	0,06	0,32	30,24	0,14

The second sample from the fragment U-405 is a section of the plaster base with a blue paint layer (Fig. 2). The results of chemical analysis of one section of the second sample (sample No. 10/1) showed that its composition includes gypsum, Cu-containing pigment, finely disperse quartz and aluminosilicates (Table 2A). Another section of the second sample No. 10/2 consists of quartz, aluminosilicates, gypsum (traces), calcite and iron hydroxides (Table 2B). Analysis of the second sample indicates that the paint layer of this wall painting’s fragment contains animal glue as a binder.

Table 2. The chemical composition of the sample of the paint layer of the mural fragment U-405, sample No. 10/1-2.

Oxides	Al2O3	SiO2	Р2О5	SO2	K2O	CaO	TiO2	Сr2O3	MnO	Fe2O3	CuO	ZnO ВаО
1	2	3	4	5	6	7	8	9	10	11	12	13
A. 10/1 Composition, mass.%	4,16	47,84	0,57	9,92	0,81	17,81	0,18	0,15	0,02	2,22	16,12	0,18 0,06
B. 10/2 Composition, mass.%	14,24	52,30	0,09	1,53	4,50	10,56	0,89	0,04	0,17	15,60	0,07	-

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 the plant filler in the form of chopped straw, the impressions of which have been preserved on the plaster.