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Heilbrunn Timeline of Art History Essays

Ceramic Technology in the Seljuq Period: Stonepaste in Syria and Iran in the Eleventh Century

Ceramic production in the Islamic lands from Egypt to Central Asia saw a major change in the second half of the eleventh century, when the development of a new medium known today as stonepaste in part replaced earthenware and sparked experimentation with forms and decorative techniques. Stonepaste—also called fritware or siliceous ware—is made primarily of finely ground quartz (obtained by crushing pebbles or sand) that is mixed with small amounts of liquefied glass (glass frit or glass fragments) and refined clay for greater malleability and structure.

To understand this phenomenon, scholars have traditionally studied complete objects from museum collections that are detached from their context of retrieval and often heavily restored in modern times, including with infills of gypsum, ancient fragments belonging to other vessels, overpainting, and gilding. The integration of archaeological data from documented excavations, and of scientific analyses of the objects' materials, is key to reassess what we know of stonepaste, its technology, socioeconomic framework, and stylistic development. Medieval written sources, on the other hand, bring forth alternative ways of looking at and perceiving these vessels and their technology.


Production of stonepaste likely evolved in Egypt in the tenth and early eleventh centuries (1975.32.3) and possibly spread as a fully developed technology to Syria and Iran by the end of that period. Yet siliceous components were used in ceramics and bricks as early as the ninth century, notably in silica-based slip applied to splashed and sgraffito wares in Iraq and Iran (38.40.137); the bricks of the Qasr al-‘Ashiq palace and the Qubbat al-Sulaybiyya mausoleum in Samarra; and ceramic bodies developed in Syria and Iraq by adding glass to clay. While not stonepaste per se, these experiments demonstrate that the potential of crushed quartz was acknowledged long before stonepaste was officially developed.

The theory of a diffusion of stonepaste technology from Egypt is supported by similarities in early Syrian and Iranian productions, such as in the composition of this material, some shapes of the vessels, and decoration. However, this understanding undervalues existing divergences between the two regions' earliest productions and is likely to be challenged in the near future by new archaeological research. Excavated assemblages often include large variations, such as objects more closely linked to localized conditions or of coarser quality, thereby restituting a more nuanced view of the overall circumstances.

A potentially significant contribution to the discussion lies in a group of earthenware vessels with comparable shapes, dimensions, and thinness and with a similar taste for elaborate rims and applied decoration as those of the early Iranian stonepaste group. They are covered with an opaque turquoise glaze, which makes their appearance seem identical to that of turquoise-glazed stonepaste. The vessels were excavated in late eleventh-century layers at the Masjid-i Juma ‘a in Isfahan, together with the earliest stonepaste but in much smaller quantities; in an eleventh- or twelfth-century phase at Istakhr; and at Nishapur, also in small quantities (38.40.24338.40.244). Further investigations will elucidate if this ware was made in imitation of stonepaste, perhaps by craftsmen not knowledgeable in the medium; if it was a preexisting production whose repertory of shapes was later adopted by stonepaste manufacturers; or if it was a transitional ware.

Beyond this physical evidence, texts from as early as the mid-tenth century refer to the use of siliceous materials in Iranian territories. The Risala (Epistle) of Abu Dulaf mentions a technique he encountered during his travels in central Iran (ca. 943–52): “Chinese pottery is white or some other color, either translucent or not translucent. It is made in the country of Fars from quartz stone, tin oxide [al-kils al-qal‘i], and glass, pounded into a paste and it is inflated and made with fire tongs just as glass is inflated in the making of cups and other vessels.” As a geographer, Abu Dulaf likely lacked the technical grounding to understand what was being described (as did the geographer who transmitted his text in the early thirteenth century, Yaqut al-Hamawi), but the mention of quartz and glass—some of the same ingredients used to make stonepaste—and the reference to “Chinese pottery” are telling. The few existing vessels of opaque glass from that time and place, all in turquoise, could have been passed off as “Chinese” on account of their often lobed and scalloped shapes, formal elements likely inspired by Chinese models. These traits, in addition to the recurrence of the same distinctive foot, suggest the possibility that stonepaste and opaque glass shared a common manufacturing environment.

Al-Biruni’s Kitab al-jawahir (Book of precious stones), completed before 1048, also mentions Chinese bowls (al-qisa al-siniyyat) in relation to a siliceous compound: “One may make [Chinese bowls] here from pure marwa [quartz pebbles], described in the chapter on glaze, mixed with clays.” The text goes on to describe how the clay was prepared and the bowls were made. Al-Biruni made no mention of glass, which may mean he described something other than stonepaste, but he did seem to witness something closer to ceramic production. Similarly, in the late twelfth-century Jawahir nama (Book of precious stones) of Muhammad b. Abu ’l-Barakat Jawhari Nishapuri, a recipe for Chinese ware also mentions ground quartz. These and other texts confirm that the fascination with Chinese pottery (presumably porcelain) must have remained strong in Iran at the turn of the eleventh century and that literate people—whose knowledge of the described technology is, admittedly, a matter of debate—perceived siliceous ingredients a component of sophisticated manufactures.

Early Stonepaste in Syria and Iran

Archaeological evidence shows that stonepaste was being produced by the last quarter of the eleventh century, and most likely earlier, in a number of centers along the Middle Euphrates, in the northwestern Jazira (Qal‘at Ja‘bar; Tell al-Fakhkhar, near Raqqa; and, possibly, Balis/Maskanah), Khurasan (Nishapur), and Jabal in central Iran (Isfahan). At that time the Great Seljuqs had taken possession of Iran and were establishing their authority in Syria, though their control over the region soon fragmented.

Ceramic production developed independently of such political changes and represented a technological and artistic evolution of established techniques stimulated by the expansion of a wealthy, mainly mercantile class that would have been the recipients, and rarely the patrons, of these objects. A large assemblage excavated in the Masjid-i Jum‘a (the Friday Mosque) in Isfahan, for example, suggests that stonepaste was widespread by the last quarter of the eleventh century and, despite its novelty, neither expensive nor particularly luxurious—at least in an urban context. The increase in the number of workshops in Syria and Iran producing stonepaste in the eleventh and twelfth centuries suggests that the technique spread rapidly and was not the prerogative of only a few craftsmen.

The earliest stonepaste vessels from Syria and Iran share several common traits. Standard shapes include bowls with slightly curving sides, everted flat or simple rims, and a peculiar, obliquely cut foot not found on other wares, all displaying a novel and remarkable thinness (23.162.320.120.216). While a close connection undoubtedly exists between vessels made in Syria and Iran, how the two regions’ industries interacted or what role local ceramic traditions played is not clear and even sparser information available for southern Jazira and Iraq preclude a detailed comparison of their manufacture. What is certain is that Syrian and Iranian specimens diverged more widely in technique, decoration, and style over the course of the twelfth century.

Early Syrian potters experimented with painting techniques, and their vessels are notable for lead-based monochrome glazes with occasional in-glaze splashes of color, often on unadorned surfaces but sometimes on those that are incised and carved or—rarer still—that bear a molded motif (a technique known as laqabi; 1979.210). Late eleventh-century fragments excavated at the Damascus citadel suggest that these potters also drew on local underglaze painting traditions (13.190.156), a development that would make it the most common decorative technique in the region (34.71, 41.165.2). Early Syrian stonepaste is often labeled “Tell Minis” ware (66.37) for an assemblage said to have been recovered in the eponymous village near Ma‘arrat al-Nu‘man, in Syria. However, since the artifacts were detached from their archaeological context and sold on the antiquities market, there is no evidence showing that they were manufactured there.

The repertoire of early central Iranian stonepaste excavated at Isfahan and Rayy included a range of inventive shapes—small vessels (48.101.2193, 48.101.2183); neckless jars with ring handles; dimpled walls; scalloped, lobed, and variably decorated rims; flower-shaped supports—some of which appear to have been inspired by metalwork or Song-period Chinese ceramics and porcelains (1974.14). This formal creativity may have stemmed from earlier examples of Iranian earthenware, especially sgraffito vessels with decorated rims and the opaque-turquoise vessels excavated at Nishapur (38.40.24338.40.244), which probably convey local responses to imports from China. 

Balancing the novelty of shapes in Iranian stonepaste is a simple palette of lead-based monochrome glazes similar to those employed in Syria: colorless, opaque white, turquoise, purple (20.120.215), and blue, sometimes in combination, on the exterior and interior of objects. Apart from an occasional splash of a second color or carved scrolls, epigraphic elements (29.160.8), or animal motifs (12.72.4), no other decorations enrich their surfaces. Some vessels were pierced before glazing, a technique almost nonexistent in Syria that would appear with increasing frequency in Iran in the twelfth century (68.223.9). Most of these Iranian vessels were produced with molds (63.159.3; 48.101.5a–c) whose use was likely meant to counter the stiffness of the siliceous compound while increasing the speed of production. While less information on manufacturing techniques is available for Syria, excavations at Isfahan and Nishapur confirm that Iranian stonepaste bowls were fired in saggers, protective fireclay vessels that enclose ceramic ware during firing (48.101.30).

The similarity of many aspects of the early Syrian and Iranian stonepaste productions (basic shapes, colors, and styles of carving) can be understood within a shared and interacting visual language within the frame of a highly connected medieval world. The correspondence of specific, technical features (the obliquely cut foot, the lead glaze), on the other hand, has been most frequently explained via the aforementioned theory of a common derivation. This hypothesis does not fully explain the broader repertory of shapes observed in central Iranian monochrome stonepaste, a possible explanation of which could be that production began some decades earlier than the (archaeologically attested) mid-eleventh century, by which time manufactures in the two regions had already begun to develop their products independently.

Further complicating the scenario, to the east, early stonepaste assemblages from Khurasan (such as those from Nishapur) share with Syria and central Iran the standard repertory of shapes but do not include either decorated or lobed rims or bowls, suggesting that development of the medium followed a slightly different path in the region (48.101.2268). A distinct local development has been attested in twelfth-century Afghanistan (1998.371).


Another decorative technique common to both Syrian and Iranian stonepaste is luster painting, first developed on ceramics in ninth-century Iraq. In this technology, a mixture containing metallic-oxide pigments is applied to a finished, glazed object, which is then given a supplementary firing (in a reduced, low-oxygen atmosphere) that chemically transforms the pigment into an impalpable sheen.

Luster-painted stonepaste vessels produced in Syria (66.37, 1975.32.2) feature a variety of geometric, vegetal, and figural motifs including seated figures, harpies, griffins, winged horses, lions, hares, eagles, and other real and fantastic animals showing an evident link to Egyptian examples (1970.23). Some of these early pieces are scratch decorated, and inscriptions are limited to benedictions or names written in Arabic kufic script. The glaze onto which luster was applied was usually transparent and colorless or opaque and white, though sometimes cobalt blue or purple; opaque turquoise glazes (64.274.1, 13.190.197) were rare, increasingly so in the later twelfth century.

The timeline for luster’s emergence is a subject of debate. Some scholars argue that stonepaste and luster developed in Syria and Iran almost simultaneously and coincident with their hypothesized diffusion from Egypt. While stratigraphic data suggest that luster was applied to stonepaste very early on, it is regularly absent from the excavated assemblages of the earliest such wares in Syria and Iran; finds from eleventh-century contexts at the citadel of Damascus are a unique exception. Archeologically sound information on the emergence of Iranian luster (16.87) is scant, but fragments have been found in archaeological layers dating from the last quarter of the eleventh century in the Masjid-i Jum'a in Isfahan, Siraf, Rayy, and Nishapur. Scholars, however, have often relied to the much later pieces inscribed with a year to reconstruct a chronology for stonepaste. The earliest of these, a bottle currently held at the British Museum, dates to A.H. 575/1179 A.D.

As for luster production centers, archaeological data are rarely helpful in identifying them. Epigraphic and historical sources and petrographic analyses, on the other hand, suggest that Iranian luster was the prerogative of a small number of family-run potteries in the town of Kashan. The late twelfth-century Jawahir Nama (Book of precious stones) of Muhammad b. Abu ’l-Barakat Jawhari Nishapuri, implies that Isfahan was also a place of manufacture, but remains an isolated piece of evidence. A corpus excavated at Gritille in southern Anatolia, which was likely produced in the region in the second half of the twelfth century, challenges the notion of centralized luster production also in Syria.