early islamic lustre from egypt, syria and iran (10th to 13th century ad

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Journal of Archaeological Science 35 (2008) 2649–2662

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Journal of Archaeological Science

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Early Islamic lustre from Egypt, Syria and Iran (10th to 13th century AD)

T. Pradell a,*, J. Molera b, A.D. Smith c, M.S. Tite d

a Departament de Fısica i Enginyeria Nuclear, UPC, campus Baix Llobregat, ESAB, Av. Canal Olımpic 15, 08860 Castelldefels, Spainb GRMA, Departament de IACA, Universitat de Vic, campus Torre dels Frares, 08500 Vic, Spainc STFC, SRS Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD, UKd Research Laboratory for Archaeology and the History of Art, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY, UK

a r t i c l e i n f o

Article history:Received 18 January 2008Received in revised form 30 April 2008Accepted 14 May 2008

Keywords:LustreIslamicMetal nanoparticles

* Corresponding author. Tel.: þ34 935521129; fax:E-mail address: [email protected] (T. Pradel

0305-4403/$ – see front matter � 2008 Elsevier Ltd.doi:10.1016/j.jas.2008.05.011

a b s t r a c t

This paper presents a study of a representative selection of lustre ceramics dating from the last quarter ofthe 10th century AD to the second half of the 13th century AD from Egypt, Syria and Iran. The studyconcentrates on the structure and chemistry of the lustre itself over the historical period considered andhas found a number of significant similarities between the production centres studied. Previous work onthe reproduction of lustre under laboratory-controlled conditions allows the archaeological data to berelated to the historical technological aspects of lustre production. The results obtained, although re-stricted to the limited number of samples studied, have demonstrated the occurrence of significantdifferences and similarities between lustre productions during this period. The possible reasons for thesechanges are discussed.

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1. Introduction

The first lustre-decorated ceramics were produced in Basra, Iraqduring the 9th century AD (Mason, 2004), a production that lasteduntil the end of the Abbasid dynasty at the end of the 10th centuryAD. During the 10th century AD the earlier polychrome lustre of the9th century was substituted by a more standardised green-goldenmonochrome production. The lustre production is linked to theintroduction of lead in the glaze formulation, through the use ofa mix of tin/lead calx added to the alkaline glaze mixture. Thechange from a polychrome Cu/Ag mixed lustre to the pure silvergreen-golden lustre was also encouraged by developments allow-ing the simplification of the production of metallic golden shines.These first lustre productions have been the subject of a previouspaper (Pradell et al., 2008a).

Although the first local Egyptian lustre production has beentraditionally attributed to the Tulunids (Caiger-Smith, 1991),chemical and petrographical studies attribute these lustrewares tothe importation of Iraqi monochrome lustre from Basra (Mason,2004). In AD 969, during a period coinciding with the decline of theAbbasid empire, the Fatimids captured Fustat and subsequentlyestablished workshops there (Caiger-Smith, 1991). The earliestdated Fustat lustre pieces are from 1000 AD and although a fullchronology has still to be established, the lustre production isknown to have lasted until the end of the Fatimid dynasty (Philon,

þ34 935521001.l).

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1980; Watson, 1985). The earliest lustre decorations show bands ofdecoration in thick line paint and display strong stylistic links withthe Iraqi monochrome lustre. The most characteristic Fatimid lustre,exhibiting new motifs of a central figure line-drawn on a plainbackground, starts to appear during the 11th century AD (Philon,1980). The use of incised lustre decorations, obtained by scratchingthe lustre surface after painting dates to circa 1100 AD (Philon,1980; Mason, 2004). The colours of Egyptian lustre are quite varied;the most common being yellow, green and brown-golden lustres.Egyptian lustre was produced over a wide variety of ceramic pastes(stonepaste, creamy and pinkish clays) and using mostly white, butsometimes turquoise and blue opaque glazes (Mason, 2004). From1100 AD onwards a light-greenish-tinged glaze was used, probablyin an attempt to imitate the Chinese green celadons (Philon, 1980;Keblow Bernsted, 2003; Mason, 2004). This fact, together with thelarge variety and low quality of some of vessel forms has given riseto the belief that there was a division of work between the potterswho produced the vessels and the glazes, and those responsible forthe lustre (Caiger-Smith, 1991). By the end of the Fatimid pro-duction, mustard lustres applied over a transparent glaze similar tolater Syrian productions were also produced (Philon, 1980; Caiger-Smith, 1991).

The destruction of Fustat in AD 1168 by Shirkuh was followed bythe rule of his nephew Salah-el-Din. During the late Fatimid period,Syria was in a state of nearly permanent war, but periods of relativepeace did permit the development of the ceramic industry (Porter,1981). Tell Minis and Raqqa lustres date to this period. Tell Miniswares show similar ceramic forms, lustre designs and colours to theFatimid lustres, and have been attributed to Egyptian potters

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arriving at Syria after 1075 AD (Mason, 2004). They date to late 11thAD (Mason, 2004) or the start of the 12th century AD (Porter andWatson, 1987). The Syrian ceramics were made of stonepaste anduse both tin-opaque and transparent lead–alkali glazes (Porter,1981; Porter and Watson, 1987; Mason, 2004). At some point in the12th century AD, the lustre production switched to the use oftransparent alkaline glazes showing, quite often, a faint greenishtinge. Some local productions of lustre have been identified duringstudies of the materials found in the excavations in Hama and alsoin the collection of materials coming from Ma’arrat al Numan(Porter and Watson, 1987). These are of low quality with some ofthem imitating Iranian lustre designs of the 12th century AD. Af-terwards, there is a gap in lustre production until the first quarter ofthe 13th century AD when a chocolate brown and yellowish greenlustre was produced in Raqqa (Porter and Watson, 1987; Mason,2004). In AD 1250 the Mongol occupation of Syria destroyed largeareas in the north of the country, terminating the Raqqa production.However, jars and albarellos of golden lustre over cobalt-blue andwhite grounds continued to be exported from Syria in largequantities during the 14th century AD. This production is typifiedby a jar with a green-golden lustre on a cobalt-blue glaze andsigned by Yusuf from Damascus (Porter, 1981).

Watson (1985) disregards the link between late 12th centuryIranian lustre and earlier local Persian ceramics production andinstead establishes a direct link between the beginning of the lustreproduction in Persia and the fall of the Fatimid dynasty. The earliestdated lustre piece from Persia is from AD 1179 (in the so calledMonumental style) and shows similar designs and decorations toFatimid lustre (Watson, 1985); later, the so called Miniature stylewhich is similar, but with more intricate and smaller designs wasproduced. By the end of the 12th century AD, this evolved into themost prolific and characteristic Kashan style of the first quarter ofthe 13th century AD. The Kashan style was a relatively standardisedhigh quality lustre that was most probably produced with a thickerlustre paint that allowed drawing and scrolling by scratching. ThePersian lustreware is made on a stonepaste body with a tin-opa-cified glaze and is of a homogenous dark-brown-golden colour,quite often with red edges. The Mongol invasion of AD 1220 dis-rupted lustre production, and there is no known dated lustrewarebetween AD 1226 and 1261 (Watson, 1985). Between AD 1260 and1280, a limited production of lustre ceramics begins again, thisshows new influences from Chinese porcelains and is known as theIl-Khanid production. This is combined with a significant growth inthe use of high quality lustre in tile manufacture (Watson, 1985;Porter, 1995).

Lustre is produced by painting the decorations over glazed ce-ramics, followed by a further firing process. The lustre techniquewas also quite innovative as the lustre layer forms from the reactionof the lustre paint with the glaze surface. This reaction involves aninitial ionic exchange of the metal ions from the paint with thealkali ions in the glaze, followed by a reduction of the metal ions inthe glaze to form metal nanoparticles (Pradell et al., 2005). Theremaining lustre paint is removed afterwards to reveal the lustredecoration embodied in the glaze. The requirement for multiplefirings, the use of expensive raw materials and exacting productiontechniques means that lustreware is an expensive art form and theproduct of skilled artisans.

This paper studies a selection of lustreware belonging to theAshmolean Museum from Egypt, Iran and Syria, dating from the lastquarter of the 10th century AD to second half of the 13th century.The selection covers most of the lustreware productions throughthis period. The object of this paper is to determine the connectionsbetween the lustre productions and the evolution of the technologyduring this time, demonstrating the key similarities and differencesand indicating the possible reasons for those changes. Previouswork on reproduction of lustre under laboratory-controlled

conditions (Molera et al., 2007; Pradell et al., 2007, 2008b) hasallowed the archaeological data to be related to the technologicalrequirements. Earlier Iraqi lustre was studied in detail in a previouspaper (Pradell et al., 2008a). The number of samples selected isnecessarily low due to the complexities of the analyses undertaken,and it is anticipated that this study will form the basis for moreextensive subsequent investigations.

2. Analytical techniques

The analytical techniques chosen to analyse the glazes and thelustre layers are the same as used in the previous work for theanalysis of Iraqi lustres (Pradell et al., 2008a). Chemical analysis ofsurfaces and polished sections of the glazes was obtained bya Cameca S-50 (WDX) Microprobe with experimental conditions of1 mm spot size, 15 kV and 10 nA probe current except for Na and Kfor which the probe current was reduced to 1 nA and the spot sizeincreased to about 5 mm. The crystalline species forming both gla-zes and lustre layers were determined by Synchrotron RadiationMicro X-ray Diffraction (SR-mXRD) analysis of glaze cross-sectionsand of thinned preparations from the lustre layers, at SRS Dares-bury Laboratory on beamline 9.6 using transmission geometry,0.87 Å wavelength, 200 mm spot size and recorded by CCD detector.UV–vis diffuse reflectance (DR) was measured directly from thesurface of the lustre layers. A small circular spot of 5 mm diameterwas used to collect the data. The data are presented as log(1/DR)which is equivalent to absorption for highly absorbing materials.The characteristic SPR absorption peaks associated with the metalnanoparticles responsible for lustre appear in the UV–vis spectragiving information concerning the type and size of the nano-particles (Kreibig and Vollmer, 1995). Finally, the oxidation stateand local coordination of Cu and Ag in the lustre layers was de-termined by X-ray Absorption Near Edge Spectroscopy (XANES)and Extended X-ray Absorption Fine Structure (EXAFS) (Sayerset al., 1971). Cu and Ag L-edge and K-edges were recorded; themeasurements being taken in fluorescence mode at SRS Daresburylaboratory with a focal spot of 2 mm on beamline 3.4 for the Cu andAg L-edges, with 2 mm spot size on beamline 16.5 for the Ag K-edgeand with sub-50 mm focal spot in the microfocus spectroscopybeamline 9.2 for the Cu K-edge.

3. Sample selection

The samples from Egypt, Syria and Iran have been selected onthe basis of chronology where available, or by the physical prop-erties of glaze and pastes that can be related to the chronology ofother studies (Mason, 2004), taking into account differences in thecharacteristics of the lustre such as colour and metal shine. Figs. 1–3show images of the samples selected from Egypt, Syria and Iran,respectively.

The Fatimid samples selected belong to the collection of sherdsfrom Fustat in the Ashmolean Museum (see Fig. 1). Sample P92 isfrom a closed form and has a yellow/greenish lustre paint appliedover a translucent glaze on a creamy paste. It has a design repre-sentative of the early Fatimid productions and could be related tolustres dating from the late 10th AD (Philon, 1980). Sample P167 isfrom an open form, painted on both sides with a yellow lustre onthe front and a yellow/greenish non-metallic lustre on the back alsocorresponding to early lustres and is related to the lustres dating tothe early 11th AD (Philon, 1980). The rest of the samples correspondto the bulk of Fatimid lustre production during the 11th and firsthalf of the 12th century AD (sample P164 has been dated to 1025–1075 AD by Mason, 2004). P164, P114, P115 and P187 show intricatedesigns and incised lustre decorations. These samples showtranslucent (P164), creamy opaque (P187) and white opaque (P167,P114 and P115) glazes. P169 shows the bluish tin-opacified lead

Fig. 1. Selection of the Egyptian lustres studied.

T. Pradell et al. / Journal of Archaeological Science 35 (2008) 2649–2662 2651

glaze produced after 1100 AD. The bodies are made of eitherpinkish (P164 and P187) or creamy (P114, P115 and P169) clays.They show yellow/greenish (P187 and P114), amber (P164) andbrown lustres (P169 and P115) with golden shine (P114, P169 andP115) or without metallic shine (P164 and P187). There is no samplebelonging to the late red lustres on transparent glazes applied overa white slip as produced at the end of the Fatimid production.

Two samples from Syrian lustreware were selected and areshown in Fig. 2. The first sample, SMN, is from the collection ofsherds from Ma’arrat al Numan (Porter and Watson, 1987). It is ofa closed form, decorated on the outside with a bright red rubylustre lacking metallic shine and painted in intercrossed thick lines

over a greenish-tinged transparent glaze. It bears similarities toRaqqa ware, circa 1200–1250 AD, and may have originated fromthere (Mason, personal communication). The second, samplep9404, is a conical bowl from Abu Sudairah. The lustre pattern isa spiral back motif of a brown chocolate colour without metallicshine, applied over a greenish transparent glaze. The form of thebowl is characteristic of those from Raqqa dated to the first half ofthe 13th century AD (Mason, 2004). There were no samples of ei-ther the earlier Tell Minis or the later Damascius lustres available.

Four samples of Iranian lustreware were selected as shown inFig. 3; samples P10321 and P10326 come from dish edges of a stylethat is transitional between the Miniature and Kashan styles and

Fig. 2. Selection of the Syrian lustres studied.


show the painted stippled scrolling decoration characteristic of thelast years of the 12th century AD (Watson, 1985). The lustre isa brown-golden colour with coppery edges and some cobalt-bluestains. Sample p10327 is the edge of a dish with the characteristicKashan style inscription scratched through a band of green lustrewithout metallic shine and dated to the first quarter of the 13thcentury AD (Watson, 1985). Finally, a tile from the Al-Khanid perioddating from the second half of the 13th century (1260–1280 AD),sample P10312, shows a golden brown, red edged lustre with tur-quoise blue painted leaves (Porter, 1995). All the glazes are opaquewhite, applied to a hard white stonepaste body.

4. Results

A summary of the main characteristics such as chemical com-position, as well as the crystalline phases identified and their dis-tribution for both the glazes and the lustre layers are shown inTables 1 and 2, respectively. This study is primarily concerned withthe structure of the lustre layer, which is significantly influenced by

Fig. 3. Selection of the Ira

the glaze used. Nevertheless, some consideration is also given tothe underlying ceramic as this is characteristic of specific pro-ductions and of the value attributed to the original item.

4.1. Fatimid lustre from Egypt (969–1168 AD)

During the Fatimid period different ceramic pastes, principallycalcareous clays and stonepastes, were used in the lustre pro-duction (Philon, 1980; Keblow Bernsted, 2003; Mason, 2004). Thepastes used for P92 and P167 have a buff colour and a sandy con-sistency with small grain sizes and their analyses indicate that theyare calcareous (14–18% CaO). They correspond to the Ca-Nile1pastes described by (Mason, 2004) who ascribes their use primarilyto between the third quarter of the 10th and the first quarter of 11thcentury AD. The lack of a paste–glaze reaction layer, especiallygiven the calcareous nature of the ceramic pastes, suggests that thepastes were fired prior to the application of the glaze mixture.

P164 and P187 used pinkish calcareous ceramic pastes (above20% CaO) with a coarse filling and calcite grains (this paste was

nian lustres studied.

Table 1Chemical analysis of the Islamic glazes and lustre layers

Region SampleID

Paste Glazethickness(mm)

Glaze/paste Glazemicrostructure

Glaze composition wt%

N Na2O K2O Al2O3 SiO2 CaO MgO FeO TiO2 PbO SnO2 CuO

Egypt P92 Calcareous clayfine grain size

150 Some Px Q, Cr, SC, B 5 3.21 (0.11) 3.07 (0.14) 2.35 (0.39) 49.56 (1.53) 1.84 (0.37) 0.19(0.6) 0.29 (0.10) 0.61 (0.04) 34.28 (1.08) 0.86(0.33) b.l.d

P167 Calcareous clayfine grain size

400 Some Px Q, Cr, HC, B 5 2.81 (0.11) 2.66 (0.21) 2.18 (0.49) 45.31 (2.11) 1.41 (0.38) 0.24 (0.04) 0.14 (0.04) 0.29 (0.03) 40.19 (2.32) 2.75 (1.07) b.l.d

P164 Calcareous claycoarse grain size

400 W Q, SC, B few Px 3 7.24 (0.18) 3.03 (0.08) 1.55 (0.32) 48.41 (0.44) 4.35 (0.19) 1.96 (0.10) 0.44 (0.08) 0.19 (0.07) 31.25 (0.94) 2.35 (0.14) b.l.d

P187 Calcareous claycoarse grain size

200–400 W Q, SC, B, few Px 6 7.97 (0.06) 3.42 (0.11) 0.86 (0.12) 47.60 (0.87) 4.32 (0.13) 1.90 (0.22) 0.22 (0.09) b.l.d 31.76 (1.85) 3.60 (0.78) b.l.d

P114 High calcareous clayfine grain size

250–400 Px Q, HCþ SC, B,few Px

5 5.05 (0.23) 3.28 (0.36) 2.60 (0.9) 52.12 (2.15) 3.96(0.39) 1.13 (0.14) 0.67 (0.19) 0.29 (0.07) 24.71 (2.34) 2.70 (0.44) b.l.d

P115 High calcareous clayfine grain size

250–350 Few Px Q, HCþ SC, B,few Px

17 2.38 (0.21) 2.46 (0.09) 1.08 (0.17) 58.09 (0.93) 3.25(0.13) 0.88 (0.07) 0.68 (0.14) 0.19 (0.08) 26.36 (0.58) 3.85 (1.51) b.l.d

P169 Stonepaste 350–700 Q, Cr, SC, B 3 5.39 (1.25) 0.85 (0.05) 0.24 (0.32) 53.22 (1.39) 1.92 (0.11) 0.26 (0.13) 0.78 (0.02) 0.16 0.153 33.33 (1.00) 3.43 (0.61) 0.31 (0.01)

Syria SMN Stonepaste 320–400 Q, Cr and Px Q, Cr 6 10.75 (0.10) 2.33 (0.09) 1.63 (0.08) 72.21 (1.13) 4.39 (0.12) 3.17 (0.11) 1.48 (0.12) 0.17 (0.02) b.l.d b.l.d b.l.dP9404 Stonepaste 320–450 Q, Cr and Px Q, Cr 12 15.89 (0.20) 2.08 (0.07) 1.61 (0.10) 70.56 (0.37) 4.97 (0.11) 3.28 (0.23) 0.89 (0.06) 0.14 (0.05) b.l.d b.l.d b.l.d

Iran P10326 Stonepaste 200–250 Some Px SC, lots Px 5 6.47 (0.13) 2.01 (0.08) 1.74 (0.35) 53.90 (1.38) 3.95 (0.15) 2.31 (0.22) 0.26 (0.04) 0.16(0.05) 21.50 (1.05) 3.66 (0.31) b.l.dP10321 Stonepaste 200–250 Some Px SC, lots Px 5 4.44 (0.17) 1.23 (0.04) 1.86 (0.30) 62.39 (1.21) 4.32 (0.31) 2.23 (0.13) 0.29 (0.03) 0.13 (0.02) 18.23 (1.43) 3.94 (0.22) b.l.dP10327 Stonepaste 200–350 Some Px HC, SC, B, few Px 5 6.70 (0.29) 2.02 (0.07) 2.20 (0.64) 53.07 (1.95) 3.49 (0.19) 2.43 (0.19) 0.26 (0.02) 0.12 (0.01) 22.97 (0.82) 3.52 (0.43) b.l.dP10312 Stonepaste 300–400 Some Px HC, SC, B, few Px 5 5.50 (0.20) 2.28 (0.08) 1.45 (0.37) 55.07 (1.43) 3.19 (0.14) 3.01 (0.18) 0.28 (0.04) 0.10 (0.03) 23.66 (1.55) 3.66 (0.92) b.l.d

All the data are given in wt%. The data are averaged over N measurements the corresponding standard deviations appear in brackets. Below limit of detection (b.l.d).HC, homogeneous cassiterite; SC, some skeletons of undissolved cassiterite; B, bubbles; Px, Pyroxenes; Q, Quartz; Cr, Cristobalite; W, Wollastonite.

Table 2Summary of the composition of the lustre layers

Region Sample ID Colour Metallic shine Surface analysis wt%a % Cu/(CuþAg) Oxidation stateb Nanoparticlesc Sized (nm)

N Cu Ag

Egypt P92 Yellow/greenish NO 28 0.25 (0.09) 2.00 (0.50) 11 100 at% Ag� Ag 12 (4)P167 Amber NO 48 0.24 (0.07) 2.86 (0.75) 8 100 at% Ag� Ag 17 (4)P164 Amber NO 44 1.77 (0.39) 4.00 (1.45) 31 AgP187 Yellow/greenish NO 43 1.02 (0.42) 4.35 (1.85) 21 Ag 20 (4)P114 Green/brown Golden 43 1.02 (0.42) 3.47 (0.99) 23 Ag 20 (7)P115 Brown Golden 35 0.46 (0.36) 5.43 (2.79) 8 100% Ag� AgP169 Red edge NO 6 1.90 (0.15) 1.85 (1.61) 51 Cu2O?

Brown Golden 27 0.56 (0.24) 7.55 (1.29) 7 Ag

Syria SMN Red NO 25 6.36 (0.960) n.d. 100 58 (5) at %Cuþ–Cu� Cu 9 (3)P9404 Brown NO 9 6.88 (0.78) 2.85 (0.80) 71 82 (7) at %Cuþ–Cu� , Cu2þ? Cu, Cu2O, Ag

Iran P10326 Red edge NO 17 1.90 (1.57) 0.14 (0.25) 9360 (4) at %Cuþ–Cu�

CuBrown Golden 65 3.57 (1.12) 2.73 (0.75) 57 Ag 9 (3)

P10321 Red edge NO 33 3.41 (0.27) 1.26 (0.74) 7376(7) at %Cuþ–Cu� 100%Ag�

CuBrown Golden 49 2.46 (0.48) 3.68 (1.11) 40 Ag 18 (5)

P10327 Greenish NO 36 4.37 (0.71) 0.78 (1.00) 85 100%Cuþ Cu2O 27 (5)P10312 Red edge NO 18 3.4 (1.7) 0.34 (0.34) 91 Cu

Brown Golden 16 5.31 (1.06) 4.48 (2.03) 54 62 (5) at %Cuþ–Cu� Ag

a Microprobe analysis measured on the surface of the layers.b XANES and EXAFS analysis.c UV–vis spectroscopy/Micro-XRD.d Micro-XRD peak width analysis.

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primarily found in the group FLP1 dated 975–1025 AD and FLP2,dated 1025–1075 AD, Mason, 2004). A very thin layer (20–30 mm inthe thicker parts) of wollastonite crystals in the glaze–paste contactzone is due to the reaction between the calcareous paste and theglaze. This wollastonite reaction layer produces a white backgroundfor the lustre decorations (Mason, 2004). P169 is of a quartz richstonepaste, (more than 85% SiO2) with a creamy colour (primarilyfound in lustrewares from 1025 to 1075 AD, Mason, 2004). The ir-regular thickness of the glaze and glaze/paste interaction regionsuggests the use of a single firing of paste and glaze. Finally, P114and P115 are of highly calcareous ceramic pastes (above 30% CaO)(assigned to the groups FLP3 and FLP4 1075–1125 AD and 1125–1175 AD, Mason, 2004) and of a sandy consistency. These appearwell fired (no calcite remains) and are heavily altered (containinganalcime). The thin paste–glaze reaction layer and even sometimesthe lack of it, together with the calcareous nature of these pastesindicate a separate firing for pastes and glazes.

The glazes of all these samples have a high lead content (about30 wt% PbO) (see Table 1). However, samples P114 and P115 containsignificantly lower lead contents (Mason, 2004). The SnO2 contentquoted is of the amount dissolved in the glaze between cassiteriteprecipitates, thus it does not give the total tin content of the glazes.In particular, sample P92 contains very small amounts of SnO2 (0.9wt%) when compared with the others. Samples P92, P164 and P187show a very heterogeneous distribution of cassiterite, which formsagglomerates of smaller particles that are determined by the shapeof the original cassiterite particles and the glaze appears trans-lucent. In contrast, the rest of the samples show homogeneouslydistributed cassiterite crystals of small size in the glaze, thus en-hancing the white opacity of the glazes. A few aggregates formedon the skeletons of the original cassiterite grains are also present.Calcinating tin and lead together prior to adding them to the glazemix is more likely to produce homogeneously distributed cassit-erite particles of small size. On the contrary, if the tin oxide is mixeddirectly with the glaze raw materials, then a heterogeneous dis-tribution of cassiterite crystals resembling the original crushedcrystal structure is more likely to occur. The glaze of sample P169also shows a greenish tinge and chemical analysis indicates thepresence of small amounts of copper (0.31 wt% CuO) (Table 1).Small amounts of copper have also been found in other studies(Helary, 2003).

The lustre layers of P92 and P167 (see Table 2) are silver rich andcontain only a very small amount of copper (0.2 wt% Cu, 2–3 wt%Ag,). They show a good inverse correlation with the alkalis havinga unity slope, as shown in Fig. 4a and c. These inverse correlationswith unity slope were also found in the early Iraqi lustres and inlustre reproductions produced under laboratory conditions (Pradellet al., 2008a,b). The unity slope indicates that each Cuþ or Agþ iondiffused into the glaze surface from the lustre paint has been ex-changed by one Naþ or Kþ ion from the glaze (Pradell et al., 2005;Molera et al., 2007). This mechanism is known as ionic exchangeand ensures the charge balance is maintained as the copper andsilver ions diffuse into the glaze. The reducing atmosphere pro-duced both by the reaction of the sulfur-containing compounds inthe paint, as well as externally applied kiln atmospheres, is thenresponsible for the reduction of the Cuþ and Agþ ions to metal andthe subsequent formation of the metal nanoparticles (Pradell et al.,2004). The UV–vis spectra shown in Fig. 5a show a single redshifted and broad surface plasmon resonance (SPR) absorptionpeak which is related to the presence of independent sphericalsilver nanoparticles (Kreibig and Vollmer, 1995). The SPR peak isred shifted more for sample P167 (peak position at 450 nm) thanP92 (peak position at 437 nm). This larger red shift is responsiblefor the more yellow/orange colour of P167 compared to the yellow/green colour of P92. A larger red shift, combined with peakbroadening, is related to bigger nanoparticle sizes (Kreibig and

Vollmer, 1995). The average size (see Table 2) is 17�4 nm forsample P167 and 12� 4 nm for sample P92, determined from thepeak width analysis of the Micro-XRD spectra in transmission. Al-though this gives a good estimation of the average size of thenanoparticles in the whole layer, it does not give the size distri-bution of the particles, and it is known that big and small nano-particles are often present in the lustre layers.

The samples P164, P187 and P114 show amber, yellow greenishand green-golden colours, respectively. These are silver and copperricher (about 4 wt% Ag and 1 wt% Cu) and the relative coppercontent is also higher than in the previous lustres (see Table 2). Themetal ion content of all of these shows a good inverse correlationwith the alkalis, again with a slope of unity. These values areequivalent to the values determined for a Fatimid green lustre fromthe same period (sample 209 in Helary, 2003), with between 15wt% and 20 wt% Cu/(Agþ Cu) being determined by RBS and PIXE,respectively (Helary, 2003; Darque-Ceretti et al., 2005). The UV–visspectra (see Fig. 5a) show the presence of the SPR peak related tothe metal silver nanoparticles. These peaks are broad and showsome structure (splitting of the peaks) which is related to the in-crease in the size and volume fraction of the nanoparticles (Quintenand Kreibig, 1993; Kreibig and Vollmer, 1995). In sample P114, thevolume fraction of metal nanoparticles is high enough to show thegolden metallic shine which is not displayed by the other samples.Micro-XRD analysis shows the presence of silver nanoparticles andthe peak width analysis gives an average size of about 20� 8 nm.Previous reproduction experiments have shown that the use of leadglazes strongly favours the development of the metallic shine(Molera et al., 2007) by concentrating the nanoparticles in a thinnerlayer and also forming a layer of bigger nanoparticles. However, ifthe temperature is not high enough or the reducing atmosphere isnot sufficient, the metal shine is not developed even in lead con-taining glazes (Molera et al., 2007). The previous Fatimid lustresstudied (P92 and P167) as well as P164 lacked metallic shine.Sample P187 showed some shine in the form of small brilliantpoints, but not a fully developed golden shine. The large number oflustres lacking metallic shine indicates that attaining the correctfiring conditions for full lustre development was not easilyachieved.

P169 and P115 show a silver rich and copper poor, brown-goldenlustre (Table 2 and Fig. 4b). Chemical analysis of both lustre surfacesshows a good linear inverse correlation between the metals and thealkalis but with a slope greater than unity (see Fig. 4d). Thesesteeper profiles have also been found in other cases (Pradell et al.,2005, 2008a; Molera et al., 2007; Roque et al., 2007). These profilesarise because alkali ions from a deeper thickness than that occupiedby the metal nanoparticle layer have been involved in the ionicexchange. This is related to the growth of the metal nanoparticlesand so the presence of these steeper profiles may indicate the use ofa stronger reduction or a longer reducing period.

UV–vis spectra from P169 and P115, Fig. 5a, show a flat asym-metric double SPR peak (380 nm and 450 nm) with high tails atlarge wavelengths. This is characteristic of a high density of silvernanoparticles and is responsible for the golden shine, the broaddistribution of sizes being responsible for the brown colour(Farbman et al., 1992; Kreibig and Vollmer, 1995; Reillon andBerthier, 2006; Molera et al., 2007; Pradell et al., 2007). Ag L3-edgeEXAFS data from sample P115, Fig. 5b and c, indicates that all thesilver is present as metal. Sample P169 shows also the presence ofreddish edges which are copper rich and silver poor (see Fig. 4b).The formation of red edges has been related to the easier access ofthe furnace atmosphere to this area of the decoration, as the changefrom oxidising to strong reducing conditions favours the de-velopment of a copper red lustre (Molera et al., 2007). This has alsobeen observed for early Hispano Moresque lustres from Paterna(late 13th century AD) (Smith et al., 2006). Finally, the broad

P169

0 1 2 3at%Na

0

1

2

3

at%

(C

u+

Ag

)

d

0 1 2 3 4at%(Na+K)

0

1

2

3

4

at%

(C

u+

Ag

)

c

P92

0 400 800 1200 1600 2000d (μμm)

0

1

2

3

wt%

Na

K

Cu

Aga

Na

K Cu

Ag

0 400 800 1200 1600 2000 2400d (μm)

0

2

4

6

8

10

wt%

b

Fig. 4. Ag, Cu, K and Na compositions measured across the surface for samples P92 (a) and P169 (b); correlation between metals and alkalis for samples P92 (c) and P169 (d).


absorption peak between 600 nm and 800 nm in the UV–visspectrum shown for the white glaze of P169 is related to thepresence of Cu2þ dissolved in the glaze (Gonella et al., 1998). This isresponsible for the greenish tinge shown by the glaze and thepresence of copper has also been determined by the chemicalanalysis (see Table 2 and Fig. 5a). This indicates that the reducingatmosphere used in the lustre production is less able to penetratethe interior of the glaze, with the reducing effect being concen-trated at the surface.

4.2. Syria (third quarter of 12th and 13th century AD)

Both samples studied, SMN, and the sample from Raqqa, P9404,have a transparent glaze, with a greenish tinge, applied over a buffcoloured stonepaste composed mainly of quartz grains, with a fewfeldspar grains, bonded together with some interstitial glass. Cross-sections of the glazes show an irregular reaction layer with the

paste and the chemical analyses confirm the alkaline nature of bothglazes (see Table 1). Micro-XRD analysis of the reaction layer in-dicates the presence of mainly quartz and cristobalite together withsome pyroxenes. The glaze and stonepaste are fired together ina single firing. The greenish tinge of the SMN glaze is due to thepresence of about 1.5 wt% FeO dissolved in the glaze as Fe2þ. Fe2þ insolution in glaze gives this greenish colour as in the Chineseceladons.

Sample SMN has a pure copper red ruby lustre (6.4� 0.9 wt% Cuand no silver), while P9404 has a mixed copper and silver brownchocolate lustre (6.9� 0.8 wt% Cu and 2.9� 0.8 wt% Ag). SMN hasa relatively well-preserved surface and shows a very good inversecorrelation between the Cu and Na ions, indicating that the redlustre has been produced by ionic exchange, see Fig. 6 (Pradell et al.,2005). The correlation has a slope slightly below unity, which maybe due to a reduction in the total Na content near the glaze surfacedue to Na leaching during burial. The surface of P9404 shows

Agº nanoparticles

P92

P167

a

4 3.5 3 2.5 2E(eV)

P169

P187

bP114

Cu2+

P115

300 400 500 600 700

λ(nm)

0.6

0.8

1

1.2

1.4

lo

g(1/D

R)

c

2 3 4 5 6 7

k (Å-1

)

-1

0

1

2

3

I(a.u

)

P92

P167

P115

P164

0 1 2 3 4 5 6 7 8 9 10

R (Å)

0

5

10

I(a.u

)

P92

P167

Ag-Ag1st shell

2nd shell 3rd-4th shell

P115

Fig. 5. (a) UV–vis spectra obtained from the Egyptian lustres. The full symbols correspond to the lustres and the open symbols to the glazes. The glaze corresponding to sample P169shows a broad absorption band above 600 nm that is related to the presence of Cu2þ dissolved in the glaze and responsible for the greenish tinge. (b) Ag L3-edge EXAFS spectra and(c) the corresponding Fourier Transformed data from samples P92 (green lustre), P167 (yellow lustre) and P115 (brown lustre). The FT data shows the radial atomic structuresurrounding the excited Ag atom.


significant devitrification, a characteristic pearl-like surface, andthe chemical analysis directly from the surface shows a completeloss of Na. The lustre surface is less deteriorated but the analysisshows quite low totals and it is not possible to establish any inversecorrelation between the alkalis and Cu and Ag. The glaze contains0.9 wt% FeO and has a light-greenish tinge.

Micro-XRD data from SMN, Fig. 7c, indicates the presence ofcopper nanoparticles of small size, 9� 3 nm. Similarly, smallergrain sizes of the metal nanoparticles were observed for lustresdeveloped on lead free glazes (Molera et al., 2007). UV–vis fromP9404 shows a very flat profile as is usually seen in copper/silvermixed dark brown lustres (Pradell et al., 2008a,b) and the SPR peakcorresponding to the presence of copper nanoparticles is also clear.The copper oxidation state of both lustres were studied by L2,3-edgeCu XANES. Fig. 7a shows the presence of Cuþ and Cu� (Van der Laanet al., 1992) for both the red lustre SMN and dark brown lustreP9404 from Raqqa. The ratio of copper oxide to total copper content

(Cuþ/Cutotal) is determined to be 82� 7% for sample SMN and58� 5% for P9404. Cu2þ is not observed in any of the samples.Previous studies showed that when copper and silver coexist in thelustre layer, the local redox conditions may inhibit the reduction ofCuþ to Cu� and if strong enough enhance the oxidation of Cuþ toCu2þ (Smith et al., 2006), which would explain these high oxidefractions. The use of high Fe containing glazes has also been iden-tified in Roman copper red ruby glasses (Arletti et al., 2006). Thepresence of high iron content in the glaze can enhance the re-duction of Cu2þ to Cuþ through oxidation of Fe2þ to Fe3þ. This hasbeen described to happen at high temperatures (molten glass)(Schreiber and Coolbaugh, 1995; Schreiber et al., 1999), but also atthe lustre production temperatures, above 550 �C (Kido et al.,2006).

The presence of metal copper nanoparticles is responsible forthe red ruby colour of SMN, in contrast to the brown colour ofP9404, which is mainly due to the coexistence of silver

0 1 2 3 4 5 6 7at%Na

0

1

2

3

4

5

6

7at%

Cu

b

0 1000 2000 3000d (μm)

0

2

4

6

8

10

wt% Na

K

Cu

a

Fig. 6. (a) Chemical composition measured from the surface of sample SMN, (b) cor-relation between Na and Cu ions.

b

300 400 500 600 700λ(nm)

1

1.1

1.2

1.3

1.4

1.5

lo

g(1/D

R)

4 3.5 3 2.5 2

20 30 402θ

In

ten

sity (a.u

.)

Cuº

E(eV)

SMN

P9404

a

930 940 950 960 970 980Photon energy (eV)

0

0.004

0.008

0.012

0.016

0.02

I(a.u

)

Cu2+

Cu+

Cuo SMN

P9404

c

Fig. 7. (a) Cu L2,3-edge XANES from both Syrian lustres studied. (b) UV–vis spectrafrom both Syrian lustres. (c) Micro-XRD spectrum corresponding to the SMN lustrelayer.


nanoparticles; the UV–vis data corresponding to both samples areshown in Fig. 7b showing the presence of the SPR peaks corre-sponding to the copper nanoparticles (560 nm). The addition ofcopper helps the growth of the silver nanoparticles in the glaze(with large red shifts of the SPR peaks) thus improving the for-mation of the dark brown lustre and producing the flat UV–visspectrum for lustre P9404. Consequently, pure silver lustres aremore likely to show green and yellow colours, whereas mixedcopper and silver lustres give a brown colour. The brown coloursare also linked to good reduction, if the reduction is not completethen yellow and amber colours are produced. The thickness of thelustre paint is also important in determining the colour; very thinpaints may produce yellow colours even though a good reduction isperformed (Pradell et al., 2008b). There are some lustres fromRaqqa (e.g. a Raqqa jar on display in the British Museum) showingthese silver greenish/yellow and amber colours (Porter, 1981; Por-ter and Watson, 1987). Finally, this type of lustreware does notshow metallic shine, which is to be expected for lead free glazes(Pradell et al., 2008a).

4.3. Iran (third quarter of the 12th century AD and 13thcentury AD)

Iranian lustreware was made of a very characteristic hard andwhite stonepaste in contrast to other contemporary Iranian pro-ductions which came from the same workshops (Kingery andVandiver, 1985; Keblow Bernsted, 2003; Mason, 2004). Accordingto the 14th century AD treatise of Abu’l-Qasim (Allan, 1973) thepaste was made by mixing 10 parts of fine white sand with one partof a glass frit and one part of white clay. Micro-XRD analysis of the


paste corresponds very well with this formulation, identifying theoriginal sand made of quartz and feldspars, and nepheline andpyroxenes formed by the reaction of the sand with the glass frit.The presence of nepheline suggests a high firing temperature,which is in agreement with petrographic studies (Keblow Bernsted,2003). The glazes are tin-opacified and lead rich, about 20 wt% PbO,although the lead content is lower than for the Fatimid production(see Table 1). These results agree with other studies (Kingery andVandiver, 1985; Borgia et al., 2004; Mason, 2004). The glazes con-tain cassiterite (SnO2), quartz, pyroxenes and some feldspar grains.In the glazes of the 12th century AD samples (P10321 and P10326)cassiterite appears in the form of aggregates which are heteroge-neously distributed, whereas in the 13th century AD glazes (sam-ples P10327 and P10312) cassiterite appears more homogeneouslydistributed, although some aggregates are also observed. Moreover,the other crystalline phases (pyroxenes, quartz) are greatly reducedin number and size compared to the earlier samples P10321 andP10326. The homogeneous distribution and small size of cassiteritemay indicate the pre-fritting of the lead and tin before mixing withthe sand particles and plant ashes. In all cases the glazes and pasteswere fired in a single firing.

c

P10321

0 1 2 3 4at%(Na+K)

0

1

2

3

4

at%

(C

u+

Ag

)

b

0 1000 2000 3000 4000 5000d (μm)

0

2

4

6

wt%

Na

K

Cu

Ag

a

Fig. 8. Ag, Cu, K and Na composition measured across the surface of samples P10321 (a) and(b) and P10312 (d): white glaze (grey dots); red edge (red dots) and brown-golden lustre (brois referred to the web version of this article.).

The 12th century AD lustres, P10321 and P10326, are similar.Both show a dark-brown-golden lustre with red edges (see Fig. 8a).The chemical analysis indicates the presence of both copper andsilver (2.7� 0.8 wt% Cu, 3.6�1.1 wt% Ag); but the copper content isvery high compared to the Fatimid samples. The metals show in-verse unity correlation with the alkalis, as shown in Fig. 8. UV–visspectra show the characteristic double SPR peak (at 380 nm and450 nm) corresponding to a high volume fraction of silver nano-particles in metallic shining lustres (Dusemund et al., 1991;Farbman et al., 1992; Quinten and Kreibig, 1993; Molera et al., 2007)with a small SPR peak corresponding to the presence of somecopper nanoparticles. However, the Micro-XRD pattern shows onlythe presence of silver nanoparticles (average size of 18� 5 nm),suggesting that the copper nanoparticles are too small and/orpresent in very small amounts. This corresponds well with TEManalysis of Iranian lustres from this period (Kingery and Vandiver,1985; Borgia et al., 2004). The red edges are silver poorer (3.4� 0.3wt% Cu, 1.3� 0.7 wt% Ag) and show a more intense SPR peak relatedto the metal copper nanoparticles (565 nm), Fig. 9a. Cu L2,3-edgeXANES of the whole lustre layer shows the presence of Cuþ and Cu�

with a high Cuþ/Ctotal ratio, 60� 4% for P10326 and 74� 6% for

0 400 800 1200d (μμm)

0

2

4

6

8

wt%

Na

K

Cu

Ag

0 1 2 3 4 5at%Na

0

1

2

3

4

5at%

(C

u+

Ag

)

d

P10312

P10312 (c). Corresponding correlation between metals and alkalis for samples P10321wn dots) (For interpretation of the references to colour in this figure legend, the reader

P10327

940 960 980Photon energy (eV)

0

0.01

0.02

0.03

0.04

I(a.u

)

Cu2+

Cu+

Cu0 P10326

P10321

b

300 400 500 600 700λ(nm)

0.9

1

1.1

1.2

1.3

1.4

lo

g(1/D

R)

4 3.5 3 2.5 2E(eV)

Cuº nanoparticles

Agº nanoparticles

P10321

Cu2O nanoparticlesP10327

Cuº nanoparticles

P10312

a

P10326

Fig. 9. (a) UV–vis spectra corresponding to the brown (open circles) and red (full circles) areas from the Iranian lustres samples P10321 and P10312 and from the greenish (fullsquares) surface from P10327. (b) Corresponding Cu L2,3-edge XANES spectra.


P10321, as shown in Fig. 9b and Table 2. A high Cuþ ratio wasobtained from an Iranian lustre from the same period (80% forsample Ira9) (Padovani et al., 2006); the SPR peak corresponding tothe copper metal nanoparticles was also observed. The copperoxide fraction is very high, but this is expected to happen in silverrich regions, and both the brown and the red areas are more silverrich than the later Hispano Moresque productions (Smith et al.,2006). Cu K-edge EXAFS data were collected from a series of loca-tions on P10321, Fig. 10a, including from within the red edge. Al-though individual spectra were not of sufficient quality for detailed

0 1 2 3 4 5 6 7 8 9 10

R(Å)

0

5

10

F(R

) (a.u

.)

Cu-O

Cu-Cu

2nd-4th shell - metalCu-Cu

1st shell-metal

1st shell - oxide

4 8 12k(Å

-1)

-1.5-1

-0.50

0.51

1.5

χ(*k

2)

a

Fig. 10. (a) Cu K-edge EXAFS spectrum (top) and the corresponding Fourier Transform (bottofrom sample P10321. Solid lines correspond to the experimental data and dashed lines to t

analysis, no discernable difference could be determined betweenthem, suggesting that the copper speciation is constant throughoutthe decoration. Averaging all the spectra together shows the pres-ence of both cuprite (Cu2O) and copper metal phases with the oxidecomprising 76� 7% of the total copper content. This agrees wellwith the Cuþ/Cutotal ratio obtained from the L-edge data. The im-plication is that the red edge is due to Cuþ dissolved in the glaze. Asthe Cu spectra are consistent throughout the decoration, it can beexpected that the red colour runs throughout the entire lustredecoration, but is masked in the brown area by the much stronger

R(Å)

0

40

80

120

160

200

F(R

) (a.u

)

k(Å-1

)

-40

-20

0

20

40

χ(*k

3)

b

0 1 2 3 4 5 6 7 8 9 10

4 8 12 16

Ag-Ag 1st shell

2nd- 4th shell

Ag-Ag

m) and (b) Ag K-edge EXAFS spectrum (top) and the corresponding Fourier Transformhe theoretical fit.


colour originating from the silver nanoparticles. The Ag K-edgeEXAFS of the brown area indicates that all the silver is in metalform, Fig. 10b.

The lustre decorations from Kashan (13th century AD, sampleP10327) are known to be very similar to the previous ones, or in anycase to have a stronger and brighter golden brown lustre. Thedarker colour has been related to the application of a thicker lustrepaint (Watson, 1985) in which scratched designs could be moreeasily made. However, the lustre piece selected in this study,P10327, shows a green/yellow colour with dark brown spots andwithout metallic shine. Chemical data indicate that the green lustreis mainly made of copper (4.4� 0.7 wt% Cu) while the dark brownspots are silver richer. There is a good inverse correlation betweenthe metals and the Na (unity slope). UV–vis spectra shows a peak at500 nm corresponding to cuprite nanoparticles (see Fig. 9a) with anaverage size of 27� 5 nm as determined by Micro-XRD. Cu L2,3-edge XANES indicate that all the copper is Cuþ, Fig. 9b and Table 2.This lustre was fired at low temperatures (below 550 �C) and inrelatively oxidising conditions, which favours the ionic exchange ofcopper (Molera et al., 2007; Pradell et al., 2008b). Very smallamounts of silver were exchanged and as usual appear in aggre-gates. The reducing conditions were not strong enough to reducecopper ions to metal and cuprite nanoparticles were produced in-stead (Molera et al., 2007). All the results indicate that this isa fragment of an unsuccessful lustre. Cu K-edge EXAFS show onlya cuprite phase, although in comparison with model compounddata, it can be seen that only the first Cu–O shell is evident in theexperimental data. This suggests that the majority of copper is stilldissolved in the glaze in largely amorphous form, with relativelysmall amounts formed as nanoparticles.

Finally, the lustre of sample P10312, a tile from the Al-Khanidperiod dating from the second half of the 13th century showsa dark-brown-golden (silvery in some places) colour rimmed incrimson red. The tile has also a turquoise blue leaf. The red areacontains mainly copper, 3.4�1.7 wt% Cu, and only a small amountof silver, 0.3� 0.3 wt% Ag; whilst the brown area has high copperand silver contents, 5.3�1.0 wt% Cu and 4.5� 2.0 wt% Ag, higherthan for the earlier Iranian lustres P10321 and P10326 (see Fig. 8c).Cu K-edge EXAFS gives a mixed cuprite/metal phase with 62� 5% ofthe copper as oxide (see Table 2). Chemical analysis data show aninverse correlation between the metals and the alkalis but witha slope greater than unity, Fig. 8d, indicating the use of a long re-ducing process. The UV–vis spectra show the double SPR peakcharacteristic of a high volume fraction of silver nanoparticles(Dusemund et al., 1991; Farbman et al., 1992; Quinten and Kreibig,1993) in the brown area and also a SPR peak at 560 nm related tothe copper nanoparticles, which is more prominent in the red area.Finally, some areas show a silvery surface, an excess of reductionand accumulation of silver producing a coalescence of the silvernanoparticles and the formation of a continuous layer.

5. Discussion

This study has concentrated on the structure and chemistry ofthe lustre itself through the historical period considered anda number of significant similarities between the different pro-duction centres have been identified. It has also identified differ-ences which demonstrate a progressive improvement in control ofthe process.

The colours of lustre are determined by the presence of silver(and/or copper) metal nanoparticles. Silver nanoparticles showa SPR absorption peak in the blue, giving the lustre a green/yellowcolour, whereas the SPR absorption peaks for copper nanoparticlesappear in the yellow giving a reddish coloured lustre. A high vol-ume fraction of nanoparticles gives a cooperative response

between them and a metallic shine results (Pradell et al., 2007;Dusemund et al., 1991; Farbman et al., 1992).

The lustre techniques began in Iraq in the 9th century AD andcoincided with the introduction of lead and tin in the glazes(Mason, 2004). Cassiterite is responsible for the white opacity inthe glazes which covers over the pinkish colours of the ceramicpastes, giving a contrasting white background for the decorations.Moreover, tin dissolved in the glaze may also act to favour the re-duction and formation of the metal nanoparticles. The presence ofPbO in the glaze also favours nanoparticle growth and encouragesthe formation of thinner and denser nanoparticle layers to yieldmetallic shining lustres (Molera et al., 2007; Pradell et al., 2007).The earliest Iraqi wares were produced using mixed lead–alkalineglazes with relatively low lead contents (Mason, 2004) and usinglustre paints with different copper and silver compositions, leadingto the development of amber, brown, red and yellow colouredlustres (Pradell et al., 2008a). In most cases, these were withoutmetallic shine. The developments of the golden shine associatedwith silver rich lustres and higher lead glazes allowed the shift frompolychrome to the monochrome green-golden production duringthe 10th century AD (Pradell et al., 2008a). Political instability inIraq in the later 10th century AD coincided with the rise of theFatimid rule in Egypt. Lustre production in this period shifted fromIraq to Egypt with the migration of potters. The Fatimid dominationof Egypt allowed the continuance and development of thelustreware.

The Fatimid lustres are also monochrome (Philon, 1980; Mason,2004) and this study shows that they are silver rich, similar to the10th century AD Iraqi lustres. They were produced using high leadcontaining glazes (the highest of all lustre productions) which fa-vours the development of the golden metallic shine, provided thatsufficient firing temperatures and reducing atmospheres are used.The presence of unsuccessful lustres and the large variety of coloursshown indicate that difficulties in controlling the firing conditionsstill persisted. Fatimid lustrewares also demonstrate a wide varietyof expertise, with both high and low quality productions havingbeen found. These include high quality pieces, signed by the artist,through to roughly painted examples (Philon, 1980; Caiger-Smith,1991). This variety is reflected in the simultaneous use of clay andstonepaste based bodies; single firing and double firing of theglazes and pastes; and the use of cassiterite as white glaze opacifier,or the presence of a white wollastonite reaction layer in the ce-ramic–glaze interface (Mason, 2004). For example, the samples(P164 and P187) that show a silver rich, non-metallic lustre wereproduced on a coarse calcareous paste and used a relativelytranslucent glaze. By comparison, of the three samples which showa golden metallic shine, two used a fine calcareous paste (P114 andP115) and the other (P169) a stonepaste, they all used white opaqueglazes. These lustres are of fine quality, particularly sample P169.The study indicates that all were fired at higher temperatures andwith adequate oxidising–reducing conditions. All these cases aresilver rich and contain very small amounts of copper.

The Syrian lustrewares studied used stonepaste bodies and al-kali glazes, which followed an existing local tradition (the area hadan old tradition of glass production). However, there are somesimilarities to contemporary pieces from the end of the Fatimidperiod (some mustard coloured lustres on pure alkali glazes havebeen described by Philon (1980)). The red ruby copper lustres(SMN) are silver free and are highly oxidised. The red colour is dueto the presence of small metal copper nanoparticles and shows upvery effectively over the greenish transparent glaze. This greenishtinge (due to the presence of Fe2þ) has also been found in Romancopper red ruby glasses (Arletti et al., 2006) and is known to be ableto enhance the reduction of Cu2þ to Cuþ (Schreiber and Coolbaugh,1995; Schreiber et al., 1999; Kido et al., 2006). The reintroduction ofsilver in the Raqqa production resulted in the formation of dark


brown lustres when fired at adequate temperatures and reducingatmospheres; although greenish and yellowish colours also resul-ted when these conditions were not met (Porter, 1981; Porter andWatson, 1987, and some jars exhibited in the British Museum). Thelack of metallic shine is characteristic of many museum pieces fromthis period and is not restricted to the samples studied. The lack ofPbO in these glazes can be expected to produce copper red rubylustres, containing both cuprite and small metal nanoparticles butwithout metallic shine, even when fired at high temperatures withhigh reducing atmospheres and for long times (Molera et al., 2007;Pradell et al., 2007). Similarly, brown non-metallic lustres areobtained when copper and silver lustres are fired in high reducingconditions, greenish, yellow and amber colours being obtained forless reducing conditions (Pradell et al., 2008a,b).

There were no pieces from the earlier Tell Minis wares availablefor this study, however, these are noted for being similar to the lateFatimid productions and show a variety of pale yellow–green andorange golden lustres. Other studies (Porter, 1981; Porter andWatson, 1987) indicate that they have both transparent and tin-opacified glazes. A study by Mason showed that mixed lead–alkaliglazes (between 12 and 22 wt% PbO) were used (Mason, 2004).There are no direct links, either stylistic (Porter, 1981) or technical,between these and the later Raqqa productions. The Raqqa wareswere of lower quality glaze and fabric compared with the Tell Minislustre (Porter and Watson, 1987). However, they have not beenanalysed in this study.

Following the destruction of Raqqa by the Mongols, lustrewarereappeared in Damascus. Well-preserved jars and albarellos ingreen/yellow golden lustre on cobalt transparent blue glazes wereexported to Europe, and are known as Damascus wares. There wereno samples from this production available for this study either.Moreover, there is no analysis of these glazes in the literature andonly a single paste analysis, which indicated the use of stonepastebodies (Mason, 2004).

The Iranian lustre production shares the same technology ofproduction as the Fatimid lustres, but with some significant dif-ferences. The Iranian potters also used a lead rich glaze, although itis noted that the quantity of lead used was lower than that used bythe Fatimid potters. They produced golden metallic shining lustreswith good consistency. Alkaline glazes (copper or cobalt tinged andtransparent) were often used to glaze the interior of the closedforms and the reverses of dishes (Watson, 1985; Mason, 2004). Amixed copper and silver lustre was used, with broadly similar silverquantities to that used in the Fatimid lustres, but with a significantlyhigher amount of copper, although not as high as in the Syrianlustres. The use of higher copper content helps the formation ofa brown lustre layer and improves the yield in lustre production(Pradell et al., 2008b). The resulting decoration is strongly colouredand of striking effect. One notable feature of the Iranian lustres isa reddish edge to the brown decorations. The brown decoration isattributable to the presence of silver nanoparticles, which in theIranian samples are of sufficient volume fraction and size to givea golden metal shine. However, the silver is not so evident in theedges and here the colour due to the copper component in thelustre predominates. This is a mixture of metal copper nano-particles with highly amorphous cuprite dissolved in the glaze andappears to be the same throughout the decoration. The use ofstonepastes and tin-opacified glazes in Iranian productions appearsto have been inherited from Egypt, as previous Iranian ceramicsused clay based pastes with high lead glazes or copper, cobalt andmanganese tinged alkali glazes (Watson, 1985; Caiger-Smith, 1991;Mason, 2004). These Iranian stonepastes are of particularly highquality and were fired at high temperatures. Calcining of the leadand tin together seems to become commonplace in the 13th cen-tury AD and improves the white opacity of the glazes. The Iranianlustre production, of which the samples studied are representative

of the ceramics kept in museums and collections, is of a very con-sistent standard and represents a full achievement in the knowl-edge and control of the lustre process.

This lustre technology is also seen to have migrated west aroundthe Mediterranean during this period, with late 13th century ADHispano Moresque productions from Paterna showing clear con-nexions to the Fatimid lustre in design (Mesquida, 2001) and theuse of lead rich and tin-opaque glazes on highly calcareous finepastes (Molera, 1996). These lustres have a higher copper concen-tration than the Fatimid lustres, being more similar to the Iranianlustres with red-rimmed, brown–greenish golden decorationswhich indicate good control of the lustre technique (Molera et al.,2001; Roque et al., 2007). Later 14th–15th century AD HispanoMoresque and 16th century AD Christian lustre productions be-come even richer in copper, with red colours and coppery metallicshines (Molera, 1996). Therefore, after the destruction of Fustat,emigration of the Fatimid potters occurred both eastwards andwestwards, taking the secrets of lustre production with them. Re-finement of the technology continued during subsequent centuries,building on the expertise developed during the period of theFatimids.

6. Conclusions

The study of early Islamic productions from Egypt, Syria andIran, combined with the previous study of Iraqi lustres (Pradellet al., 2008a) has demonstrated a commonality of technology ofmanufacture, with one significant variation. Early Iraqi productionsof the 9th century AD were made from copper and silver mixedlustres of different colours and applied to low lead containingglazes, with only occasionally metallic shine (Pradell et al., 2008a).These lustres were superseded in the 10th century AD by a highquality homogeneous monochrome golden silver rich lustre madeon lead rich glazes (Pradell et al., 2008a). This knowledge wastransferred to Egypt with the migration of potters from Iraq. TheFatimid splendour allowed the full development of the lustretechnique on very rich lead glazes to perfect a silver rich goldenlustre. Fatimid lustres do show colour changes which can be relatedto the use of different firing conditions. Subsequent migration ofpotters to Syria (Tell Minis), Iran and elsewhere (particularly Spain)extended the lustre technology all over the Islamic world. The TellMinis lustreware appears very similar to the Fatimid lustre but it hasnot been analysed in this study. By comparison, the northern Syrianproductions, whilst showing influences from the Iranian lustres,were developed using lower cost materials and a limited knowl-edge of the process. These lustres are of copper based red ruby andcopper/silver chocolate brown colours and lack metallic shine.These wares will have been of lower value and mainly produced forthe local market. Whether the potters were forced to develop a newtechnology to counter difficulties in obtaining some of the rawmaterials required for lustre production, or whether they did notfully understand the secrets of lustre and were trying to copy theproduction, is uncertain. The later Iranian and Spanish productionsdo, however, show strong links to the techniques developed by theFatimid potters to produce brown-golden and red-rimmed lustreswith metallic shine which display a high degree of control of thelustre technique.

Acknowledgements

T. Pradell wants to thank Professor J.W. Allan and the AshmoleanMuseum for providing the Islamic lustre samples. T. Pradell isfunded CyCIT grant MAT2007-60087 and Generalitat de Catalunyagrant 2005SGR00201. We also acknowledge funding by the Euro-pean Community through the Research Infrastructure Action underFP6 ‘‘Structuring the European Research Area’’ program project


numbers 43025 and 45229 and 49129 at SRS, Daresbury Labora-tory. Dr. J. Molera is funded by the program Ramon y Cajal andCyCIT grant MAT2006-11144.

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