Proceedings of the 39th International Symposium for Archaeometry, Leuven (2012) 232-237

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Chemical Composition of Beads from Building of XVIII c. of Kazan Kremlin

R. Khramchenkova1, A. Sitdikov1

1. Institute of History of Tatarstan Academy of Science, Kazan, Russia, Kremlin, rezidahram@mail.ru, sitdikov_a@mail.ru

ABSTRACT The paper describes an investigation of the chemical composition of glassware, which was found during the excavations in the Kazan Kremlin in the year 2000. The majority of glass findings are beads. Chemical analysis of the bead structure showed that most of them were made of glass which is identical to bottle glass from this building. Such glass is typical for Russian glass melted with ash in the period of the 17th – 18th centuries. This article demonstrates particular features of the micro-elemental analysis. The investigation of trace elements components showed that re-melting of various glass scraps including old beads and buttons was performed in the workshop. The master used ashes of animal bones to obtain different colours for his new beads. Archaeometrical analyses lead archaeologists to new stages of research. KEY WORDS Archaeology glass, ashes of animal bones, chemical composition. Introduction

Archaeological excavations in historical areas of old cities provide plenty of materials. Analysis of the artefacts obtained sometimes leads to unexpected discoveries. Such discoveries were made during the investigation of glass material from excavations in the Kazan Kremlin. Fig. 1. Excavation XXXIV. General view of the furnace. In the beginning of the 18th century, in the north area of the Kremlin hill, new Chief Governor apartments were built. It was a part of general reconstruction of Kazan fortress according to the fortification concept of the 18th century. In the middle of 18th century these apartments were severely

damaged by a fire and were dismantled. A watchtower was the only building left. Nowadays it is known as the leaning Soyembike Tower. A building that flanked to the basement of the governor’s house was discovered in the year 2000 (Building 30, Excavation XXXIV) (Sitdikov, A.G. 2006) (fig.1). There is a timber cellar, it has dimensions of 750 x 1360cm and consists of two frames. Frames contain soot and soil with inclusions of fritted bricks and large limestone pieces. The building existed in the first half of the 18th century and is dated from a silver ruble of the year 1713, which was put by workers under the angle of the building. This date is corroborated by other coins of the first half of the 18th century, which were found in the cellar. Remains of a furnace were found in the western frame. It had dimensions of 200 x 200 cm. The floor of the frame from the side of the hearth-stone was bricked. Beads and bottle glass were discovered in the frame among the brick piles, glass slag and limestone. The majority of the beads are twice-truncated globular beads; there are also several twice-truncated ellipsoid beads. There is only one ring-shaped bead. The total amount is 382 pieces of archaeological fragments and whole glass forms. Until now, glassware of later periods did not capture the attention of archaeologists, so publications on this theme are few. The popular object of study by foreign authors is an evolution of glass production from antiquity to the modern era (Mariacher, Giovanni, 1970; Polak A., 1975). The monograph of Stanislav Ciepiela is dedicated to glassware from the upper horizons of the Warsaw cultural layer of the 18th century (Ciepiela S., 1977). Research methodology

An emission spectrum analysis was performed to discover the composition of the glass finds. For this purpose, one sample of each different type, in terms of form and colour, was selected. 27 beads, 9 glass and bottle scraps, 2 fragments of slag and 1 ash bead were analyzed. This kind of analysis is optimal for the examination of archaeological finds. Here is a brief concept of the method. A sample of 25 mg is burned from the crater of a coal electrode in an electric arc (alternating current) up to the total evaporation. Exposure time for high-volatile elements is 30 seconds with the current of 18A.

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Fig. 2. Samples of bottle glass, scrap, slag fragments and beads. After that, the spectrum is overlapped and the sample is burned up with the current of 18A. The spectrum is obtained on a diffractional spectrograph DFS-458 and it is recorded on photographic plates PFC-03. The working grid of the spectrograph has 1800 strokes /mm. Photographic plates are displayed and fastened in standard solutions. Obtained spectrograms are scanned on a spectrophotometer MF-2. Examined samples are analyzed by a classical method of 3 etalons with state standard samples and glass standard samples.

Results and discussion The macro- and micro-elemental compositions are shown in Tables 1 and 2. The glass beads in general have the same composition as the glass fragments. Glass workshops usually used one specific recipe. However, the results in Table 1 show variety in the composition of the Kazan beads. From the chemical analysis of bead structure it was established that most of them were made of glass, which is identical to the bottle glass from the building. Some of beads and glass fragments have high contents of ! (2%-7%) and K (9%-18), which is specific to the late 18th century glass (Galibin, V.A. 2001). The concentration of elements in beads 4266 are similar to the scraps of yellow-green colour (" 1,2 and " 36, tables 1,2); and in beads 4279# and in the dark blue glass (" 23 and " 33, tables1,2) concentration of elements is near the same (including contents of Bi, Co, Ni). Samples of beads numbered 4266 of various colours have almost the same composition. However, it can be noticed that a sample of blue colour in comparison with a green-yellow sample contains larger amounts of Ca, P, Mg, Sr and Ba. It seems that blue beads were made of green-yellow beads with an addition of some ingredient. Based on the elemental analysis of production wastes and goods produced, we can suppose that it was a small workshop of an incomplete production cycle, where beads were produced from glass scrap. Several single beads differ both in composition and in decoration from all the other beads. It seems that these beads were used in the melting cycle. In addition, they were used as insets in copper buttons and earrings that were discovered in the same excavation zone. Fig. 3. Copper buttons and earrings. Another peculiarity is a correlation between Ni and Co for the majority of the investigated samples (Fig.4). This relation is non-obligatory in the case of glass coloured with cobalt. And this correlation indicates the use of a colouring agent of identical composition in all of the glassware. Possibly dark blue glass colouring was performed by the addition of corresponding components or the breakage of dark blue glass.

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Table 1. Macro-elemental composition of glass beads of Kazan Kremlin, %.

! code colour CuO MnO PbO SnO TiO P2O5 CaO Fe2O3 Al2O3 K2O MgO Na2O SiO2

1 4266 green-yellow 0.012 0.38 0.041 0.0004 0.27 4.81 19.95 0.69 2.16 12.28 1.05 3.18 54.86

2 4266 blue 0.013 0.59 0.026 0.0003 0.21 6.07 23.8 0.7 3.4 12.95 1.36 3.31 47.12

3 4268 green 0.007 0.052 0.024 0.0019 0.12 0.18 8.61 1.95 1.59 14.22 0.43 5.18 67.34 4 4269 red-brown 0.005 0.009 0.003 0.001 0.074 0.15 4.73 0.09 0.91 17.85 0.26 5.62 70.18

5 4281 yellow 0.007 0.004 13.87 5.07 0.072 0.05 6.91 0.09 0.91 13.33 0.72 3.67 55.14 6 4308 green 0.31 0.058 20.15 0.0017 0.16 0.57 10.97 0.38 1.13 3.29 1.15 6.67 55.11

7 4309 green 0.038 0.17 14.72 0.0046 0.19 0.39 10.94 6.19 1.71 3.46 0.87 6.17 55.08 8 4310 turquoise 0.59 0.17 21.12 0.0092 0.23 0.67 11.12 0.49 1.68 4.24 1.36 3.24 55.02

9 4313! d.blue 0.0063 0.23 0.0096 0.0002 0.091 0.42 5.66 0.14 2.39 3.54 0.43 3.61 83.37 10 4313" blue 0.0066 0.023 0.0047 0.0005 0.16 2.77 15.31 0.11 2.27 6.17 0.53 3.89 68.48

11 4313# d.green 0.0095 0.074 0.017 0.008 0.16 0.2 9.61 4.25 1.82 9.84 0.59 6.91 66.48 12 4313$ pink 0.061 0.023 0.011 0.001 0.12 3.21 13.84 0.13 1.71 6.44 0.42 5.07 68.53

13 4267! pink 0.011 0.073 13.82 0.011 0.11 0.67 6.43 0.099 1.19 9.35 1.12 7.65 58.87 14 4267" d.blue 0.011 0.031 8.91 0.014 0.066 0.19 3.64 0.094 0.97 10.35 0.71 8.71 65.27

15 4267# l.violet 0.012 0.027 9.12 0.015 0.13 0.13 3.22 0.11 1.53 11.25 0.54 8.12 64.21 16 4247 spotted 0.013 0.17 3.83 0.16 0.15 0.17 9.94 8.37 1.72 10.29 0.43 6.48 57.91

17 4293 yel.-brown 0.0068 0.028 0.023 0.0006 0.097 0.14 11.53 0.072 1.55 11.52 0.64 6.08 68.29 18 4271 blue 0.14 0.19 10.48 0.0006 0.16 0.13 14.65 0.089 1.61 11.79 0.89 3.38 56.57

19 4289 colourless 0.065 0.083 0.041 0.0009 0.16 0.14 12.97 0.11 1.55 14.52 3.91 1.12 65.34 20 4272 d.blue 0.613 0.25 13.07 0.059 0.15 0.13 10.08 0.17 1.68 11.21 0.39 1.44 61.03

21 4279! white 0.11 0.069 0.0014 0.0003 0.01 3.21 14.51 0.06 1.34 9.95 0.57 3.89 66.34 22 4279" blue 0.054 0.27 0.0034 0.0003 0.17 0.95 14.73 0.21 3.41 12.08 1.33 3.89 62.91

23 4279# d.blue 0.051 0.18 0.008 0.0002 0.19 0.17 14.58 0.15 3.51 13.31 1.11 4.12 62.61 24 4273! green 0.086 0.089 0.0026 0.0004 0.11 0.24 10.51 3.33 1.45 9.46 0.47 4.63 69.68

25 4273" green-blue 0.44 0.14 15.03 0.0077 0.15 0.16 11.74 0.54 1.63 9.08 0.87 3.47 56.71 26 2333 blue 0.11 0.19 0.0011 0.0004 0.38 0.67 21.79 0.59 2.68 5.77 3.52 1.35 62.91

27 302 black 0.12 1.39 0.012 0.0003 0.14 2.87 3.58 2.48 4.19 0.12 1.74 0.053 82.67 28 bone bead 0.0078 0.066 0.027 0.0007 0.084 44.65 40.6 0.11 0.002 0.39 0.60 0.48 12.71

29

Glass scrap

white 0.005 0.011 0.005 0.0007 0.098 6.92 17.59 0.22 1.49 9.97 0.54 4.24 57.82 30 green 0.012 0.16 0.002 0.0003 0.36 1.71 18.52 0.74 2.51 7.48 3.47 2.39 62.62

31 d.blue-green 0.029 0.43 0.016 0.0032 0.36 0.63 17.94 3.02 3.41 1.35 4.08 8.78 59.92

32 blue 0.016 0.17 0.003 0.0004 0.31 1.58 17.19 1.17 2.84 9.44 4.42 2.74 60.08

33 d.blue 0.0081 0.39 0.0036 0.0003 0.36 0.36 14.41 0.11 0.58 12.03 4.62 0.61 67.01 34 colourless 0.0081 0.87 0.0008 0.0003 0.15 2.36 10.36 0.45 0.61 0.18 4.76 11.17 69.03

35 l. green 0.0073 0.11 0.0007 0.0003 0.31 2.14 19.53 0.41 2.08 5.77 4.08 2.45 63.07

36 yellow-green 0.012 1.01 0.034 0.0014 0.19 8.77 20.12 2.16 2.29 10.21 3.54 1.42 50.11

37

brown-green

0.017 0.22 0.23 0.028 0.43 0.35 5.04 3.59 4.35 2.9 3.83 15.18 64.41 38 slag l.green 0.004 0.047 0.0008 0.0003 0.91 0.14 1.68 3.0 31.19 3.03 0.88 1.73 57.82

39 dark 0.004 0.21 0.0009 0.0041 0.35 0.22 1.96 21.45 6.05 0.62 0.17 0.22 64.2 ash 0.002 0.067 0.0017 0.0006 0.28 10.37 19.37 3.58 6.14 5.45 2.21 3.6 48.16

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Beads 4267 have similar composition but different colour - dark blue, pink and light violet. Only in these samples is there gold as a micro-admixture (Table 2 ! 13, 14,15). It means that the same base was used for their production. This base contained Pb components and was coloured red. A diagram of the macro-element content in relative units is presented in fig.5.

Close analysis of the behaviour of Pb, P, Ca, Mg and Mn in beads 4276 shows significant decrease in the content of these elements in the dark blue and light violet examples. The decrease of Pb, P and Mn content can be explained by the repeated heating of the glass material. But Ca and Mg are high-melting elements. This phenomenon is easy to explain, if we make an assumption that during the initial melting, the master added ashes of animal bones instead of chalk to obtain pink glass material.

Table 2. Micro-elemental composition of glass beads of Kazan Kremlin, mg/kg (10-4%).

! code colour Ag As Au B Ba Be Bi !" Cr Ga Li Nb Ni Sc Sr V Y Yb Zn Zr 1 4266 green-yellow 0.06 40 0 320 1200 0.8 0.45 6.7 10 7.7 24 5.5 23 1.9 320 9 9.1 0.9 640 97 2 4266 blue 0.03 50 0 330 3900 0.8 0.56 6.8 12 8.1 26 4.5 24 1.8 1110 10 7.1 0.87 610 81 3 4268 green 0.4 310 0 120 290 0.7 3.9 21 6.8 5.6 35 6 54 2.7 91 11 6.9 0.82 30 50 4 4269 red-brown 0.29 70 0 63 72 0.6 0.44 11 5.8 2.5 29 7.5 20 2.3 48 5 6.3 0.57 27 14 5 4281 yellow 41 30 0 12 70 0.7 38 8.5 5.1 11.1 58 7.5 4.5 1.5 75 5 6.8 0.58 33 35 6 4308 blue 14 50 0 140 400 1 1.8 9.3 15 4 29 6.7 27 3.2 390 13 7.1 0.83 58 79 7 4309 colourless 18.5 50 0 350 600 1.1 0.9 19 23 6.7 30 7.9 28 2.1 600 26 7.1 1.49 52 114 8 4310 blue 16.2 50 0 160 1340 1.2 2.2 5 22 2.5 26 5.1 24 2.2 1600 15 6.6 0.75 66 101 9 4313# d.blue 0.74 170 0 31 380 1.2 3.2 99 14 3.2 21 8 56 5.3 73 17 6.8 0.79 32 54 10 4313$ blue 0.91 1600 0 66 260 0.7 8.3 275 11 3.3 26 6.2 230 2.2 190 15 7.3 0.64 18 39 11 4313% d.green 1.7 250 0 92 200 1.3 0.3 16 15 5.7 33 7.4 38 2.6 91 16 6 0.92 25 33 12 4313& pink 3.2 2500 0 100 139 1.2 13 285 10 5.1 27 7 250 3.4 140 14 6.1 0.75 20 29 13 4267# pink 6.6 3900 23 45 79 1.3 1.9 5.2 9 3.5 24 7.4 8 1.6 425 120 7.2 0.8 22 49 14 4267$ d.blue 8.9 5500 23 37 80 1.2 1 160 7 2.6 28 8.1 14 1.9 185 24 6.4 0.72 26 33 15 4267% l.violet 5.7 6300 23 37 114 1.2 1.5 7.1 9 3.3 25 7.7 10 3.9 215 18 6.1 0.77 21 48 16 4247 spotted 16 490 0 82 415 1.0 1.6 300 14 5.6 27 8.5 20 2.8 180 16 7.8 2 26 125 17 4293 yellow 0.55 60 0 55 85 1.3 0.6 8.7 10 3.9 26 8.5 22 3.3 75 12 7 0.72 20 30 18 4271 blue 19 650 0 120 1950 1.3 7.4 240 23 4.2 30 7.2 85 2.9 380 15 9.4 1.11 22 230 19 4289 colourless 1.39 160 0 140 165 1.2 0.24 6.5 19 3.5 27 7.5 16 3.4 2250 14 7.8 0.81 22 102 20 4272 d.blue 17.5 1700 0 64 2200 1.2 9.9 535 20 3.1 29 7.7 180 3.5 375 22 7.5 0.88 23 118 21 4279# white 0.66 520 0 45 80 1.3 0.3 4 14 3 48 7.8 14 4.5 135 16 6.6 0.86 30 29 22 4279$ blue 3.3 640 0 240 260 1.2 12.5 450 23 5.6 30 6.5 255 3.6 225 19 7.4 0.89 22 75 23 4279% d.blue 0.62 210 0 31 295 1.4 170 550 22 4.8 28 8 200 5.4 215 20 13 0.91 49 73 24 4273# green 0.41 190 0 51 115 1.2 6.2 9.4 15 4.6 25 6.7 26 2.4 100 13 6.5 0.77 42 180 25 4273$ turquoise 28 930 0 195 360 1.1 2.1 5.8 24 3.9 26 7.8 25 2.7 305 19 8.1 0.99 33 94 26 2333 blue 2.1 30 0 150 940 1.1 0.35 6.5 56 7.1 24 7.2 25 5.2 680 22 19 1.7 54 210 27 302 black 1.1 60 0 11 4900 1.8 1.2 1650 18 5.8 28 12 310 9.6 750 21 16 1.3 840 230 28 bone bead 0.25 13 0 11 2000 0.6 2.2 1.8 2 1 42 6 4.5 2 470 6 5.5 0.75 830 10 29

Glass scrap

white 0.04 9900 0 100 190 0.8 0.65 6 4.2 2.5 21 5.5 18 2.1 180 7 6.6 0.69 35 18 30 green 0.67 30 0 230 2000 1.3 0.22 7 31 7.1 29 7.8 19 5.6 1250 21 19 2.1 76 190 31 d.blue-green 0.69 20 0 90 2100 1.4 0.25 8.4 43 7.1 30 7.5 16 6.2 1100 29 20 2 59 190 32 blue 0.97 50 0 76 1400 1 0.23 7.4 45 7 25 7.3 22 4.5 1000 22 15 1.7 56 180 33 d.blue 0.23 440 0 99 2800 0.9 185 280 4 1.6 31 11 580 1 190 5 9 1.0 30 70 34 colorless 0.1 30 0 17 1510 1.1 0.21 1.5 20 2.8 26 6.7 2 1.2 84 10 10 0.88 23 170 35 l.green 0.14 30 0 200 1600 1.1 0.19 5.2 27 4.1 32 8.1 10 1.9 4000 18 11 0.9 76 150 36 yellow-green 0.11 10 0 1060 2200 1.7 0.8 13 32 5 30 13 21 3 270 9 19 2.7 560 350

37

brown-green 1.8 60 0 200 190 1.3 0.33 12 200 13 33 9 31 12 420 67 25 2.6 36 180

38 slag

l.green 0.08 20 0 14 540 2.1 0.7 8 62 25 38 13 35 13 100 82 27 3.1 41 780 39 dark 0.06 20 0 31 1200 1.5 0.7 25 31 11 33 9 190 15 110 14 21 3.4 52 170 40 ash 0.18 20 0 17 2700 2.2 1 10 37 7 30 8 14 11 280 48 18 1.7 137 340

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Fig. 4. !" and Ni correlation.

Ashes contain phosphates of Ca and Mg - (Ca3(PO4)2) ! (Mg3(PO4)2). These compounds are fusible, thus significant loss of Ca and Mg during the melting is observed. A scheme of the production of beads 4267 is presented on fig.6.

Fig. 5. Diagram of macro-element content in relative units.

This assumption fully explains the difference in content of Pb, P, Mg and "a in beads 4266. Ca and Mg are not the only proofs of the use of animal bones in the melting. Increased contents of Ba and Sr are also well explained by this assumption. Chemically, Sr is situated between Ca and Ba and has one interesting feature. When soluble compounds of Ba and Sr get into an organism they accumulate in the skeleton, replacing Ca ions (Inorganic chemistry, 1975). It is known that water of Tatarstan is hard and contains considerable quantities of Ba and Sr (Hydrogeology of USSR, 1970). Thus, the source of Ba and Sr is established. It was drinking water that was consumed by animals. Two and a half bone beads were discovered in the building # 30. Their contents are provided in tables 1 and 2. Some of the glass debris also contains Ba and Sr, but this glass contains Zn in amounts less than 0.008%. In beads 4266, as well as in the bone beads, the amount of this element is larger by an order of magnitude. It can be assumed that the glass master of the Kazan Kremlin decided to use ashes as a processing aid during the glass melting, similar to the process of bone china production. It is known that bone china is obtained by an addition of the ashes of animal bones into the main components of the porcelain (Ivanov, G.M. et.al. 1985). The items obtained are very thin, extremely white and immensely strong. The use of this processing aid was in some ways an innovation in glass making. The main literature about glass only describes recipes of mixtures containing vegetable ashes. Bone ashes as a component of glass production are not mentioned. Possibly the high cost

of bone ashes and the secret of its production limited its usage.

Fig. 6. Beads production scheme. Goods of bone china were extremely expensive. Coxofemoral bones of bovine animals were used to produce this kind of porcelain. Only in the middle of the 18th century did production of bone china appear in England. The fact that the glass workshop of the Kazan Kremlin is older than the discovery of European bone china allows us to make a conclusion that the Kazan master possibly had access to investigations in this area. It should be noted that the glass maker from the Kazan Kremlin tried to use alumino-silicate components as a processing aid (possibly kaolin). This is proven by some components of the glass slag (tables 1-2, # 39, 40), which were the results of failed experiments. Big, black bead 302 (# 27 in tables 1 and 2) contains the most surprising glass. The content of this bead is not actually a glass because there is no K, Na and Pb; so it doesn’t contain any of the main glassmaking components. It looks like a natural siliceous mineral. But, the presence of P, and metamorphic changes in the upper layers of the bead, show that it is an artificially made material. It is possible that the master used some natural stone during the glass melting. But to melt quartz one needs a fluxing agent to lower the melting temperature. Phosphorus anhydrite is one such reagents. It is sometimes used today as a processing aid in quartz glass production.

Fig. 7. Black (302) and bone beads. What was the source of this reagent for the Kazan glassmaker? The obvious answer is a bone, which can contain up to 15-20% phosphorus anhydrite. It was the bone of a very young animal, which contained twice as many organic substances and Ca as compared with the bones of adult animals. The presence of N and Cl in bones can explain the degradation of the bead. The material of the bead contains larger amounts of Ba, Zn and Sr.

+bone ash

+ Co

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Fig. 8. Scheme of black bone bead production. There is also an interesting glass object among the finds of the building (! 2333). It is 20 " 20 " 10mm and a blue colour. One side of the object contains an engraved picture made by a sharp tool. Its function is unclear but it seems to have some artistic character. Judging by its chemical composition the sample was produced in the Kremlin workshop from a glass scrap. The painting on it was made in a dilettantish way (fig.11).

Fig. 9. Glass work. Other remains of glass production were also discovered in the building. There are numerous polishing slate pencils of deep grey colour, 3-4 mm in diameter with non-symmetric edges and rounded ends. Similar slate pencils with better technological processing are used today in glass production. Analogous findings were discovered on the territory of a Kazan glass factory dated to the second half of the 18th century.

Conclusions

A glass workshop in the Kazan Kremlin appeared during the period of glassmaking popularity. Glassmaking had spread all over Europe, beginning from the 17th century, after the book named "Art of glass" by a Florentine monk and the book "Ars Vitraria Experimentalis oder vollkommene Glasmacher-Kunst" by the German alchemist Johann Kunckel were published. These books revealed the secret of glassmaking and it became an accessible craft.

1. The Kremlin Master used half-stuff and various glass scrap as a source material for the production of beads.

2. The workshop had a chiefly entertaining character with some experimental component.

Besides glassware, numerous objects were found in the XXXIV cellar. They indicate that the master belonged to the nobility. Among these objects are two Dutch tobacco pipes, remains of a pistol, a ceramic female figure and so on. From all of the above, one can make a conclusion that the production of beads in this case was probably a hobby of the noble man, and this was typical for the nobility of that period. References Ciepiela, S. 1977. Szeklo osiemnastowieczene starej Warszawy. Warszawa, 254 p. Galibin, V.A. 2001. Glass composition as archaeological source. St. Petersburg: "Petersburg oriental studies ", 201-203 Hydrogeology of USSR, 1970. Volga and Kama regions. Nedra,

Moscow, 13, 471. Inorganic chemistry, 1975. Soviet encyclopedia, Moscow, 286-287. Ivanov, G.M., Kosov, V.S. and Smirnov, G.V. 1985. Mariacher and Giovanni, 1970. Glass from Antiquity to the

Renaissance. Hamlyn publishing group limited. London – New York – Sidney – Toronto, 157 pp.

Production of art ceramics/ College manual, High school, Moscow, 178.

Sitdikov, A.G. 2006. The Kazan Kremlin: historical-archaeological investigation, Kazan, 288pp.