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Inventory number: U-410

Title: Fragment of wall painting with an image of horse's head
Material: loess plaster base (clay and chopped straw), gypsum primer, mineral pigments
Front side or imprint: front side
Dimensions: 16 × 10.2 cm
Site of discovery: the temple of god Ḫaldi at Erebuni
Research laboratory that performed the study: Laboratory of chemical and technological research of the State Research Institute of Restoration (GosNIIR)

The mural fragment with the image of a horse's head is of particular interest for chemical and technological research, as it is one of the rare examples of the wall paintings from Erebuni, which has been preserved from the front side, rather than the imprint of the paint layer. Therefore, samples of both white primer and plaster base with traces of the paint layer were taken in the laboratory of chemical and technological research of the State Research Institute of Restoration. The chemical analysis of several samples of white primer (sample No. 7, Table 1) showed (Fig. 1) that its composition includes gypsum and calcite (the ratio of gypsum to calcite is 2:1).

Table 1. The chemical composition of the sample of the white primer with traces of the paint layer from the mural fragment U-410, sample No. 7.

Oxides

МgO

Al2O3

SiO2

P2O5

SO2

K2O

CaO

Fe2O3

CuO

ZnO

BaO

1

2

3

4

5

6

7

8

9

10

11

12

7. Composition, mass. %

-

-

-

0,60

41,67

-

57,52

0,17

-

-

-

The second sample was taken from the plaster base, but it was studied from both the front side of the fragment (the surface of the plaster base with the paint layer) and the back side (the lower part of the plaster base going deep into the painting fragment; Fig. 2). The element analysis of samples from the front side of the plaster base (sample No. 8/1) revealed the following chemical composition (Table 2A): the aluminosilicates, quartz, iron hydroxides, calcite, plaster (ratio of gypsum to calcite – 1.6:1). The plaster in the sample from the front surface probably represents traces of the preserved original primer. Analysis of the second sample from the back side of the mural fragment U-410 (sample No. 8/2) showed that its chemical composition includes aluminosilicates, iron hydroxides and calcite (Table 2B). However, unlike sample No. 8/1, there is no gypsum in the sample of the back side.

Table 2. The chemical composition of the sample of the plaster base from the front and back sides of the mural fragment U-410, sample No. 8/1-2.

Oxides

Al2O3

SiO2

SO2

 

Р2О5

K2O

CaO

 

TiO2

 

Сr2O3

 

MnO

Fe2O3

CuO

SrO

ZnO

ВаО

1

2

3

4

5

6

7

8

9

10

11

12

13

A.8/1. Composition, mass. %

10,80

41,23

9,14

0,35

4,06

16,29

1,32

0,05

0,23

15,76

0,51

-

0,09

0,10

B.8/2. Composition, mass. %

18,92

36,46

-

-

1,55

15,52

0,80

-

0,44

23,80

0,29

1,98

0,2

1,98

As in most of the other studied wall paintings from Erebuni, the plaster base of the mural fragment U-410 consists of loess deposits with a plant filler in the form of chopped straw.

a
b
c
d

Fig. 1. Sample of the plaster base from the mural fragment U-410 (sample No. 7, a-d – several samples of white primer).

a
b
c
d

Fig. 2. Samples of the plaster base of the paint layer with inclusions of blue pigment from the mural fragment U-410 (sample No. 8/1-2, a – the front and back of the sample No. 8/1; b-c – the front and back of the sample No. 8/2; d – the section of the sample No. 8/2 close-up).