Archetype Publications with the Freer Gallery of Art
Abstract
The palace of Kubad-Âbâd was built on the instructions of the Seljuq Sultan Alâeddin Keykubad I.
Excavations have recovered large quantities of decorated glazed wall tile, typically in the familiar “star and cross”
pattern. We have analyzed fifty tiles, using inductively coupled plasma–atomic emission spectrometry for major
elements and inductively coupled plasma–mass spectrometry for trace elements. Selected tiles were subjected to
petrographic thin-section analysis and to scanning electron microscopy–energy-dispersive x-ray spectrometry for
technological analysis of glazes and pigments. All the tiles are stonepaste bodies coated with an alkali-silica glaze.
Black underglaze decoration is typically executed in crushed chromite. Turquoise is due to copper, and deep blue
colors are due to cobalt; in some cases the cobalt pigment was mixed with fine-grained quartz to minimize bleeding
into the glaze. Luster-decorated star-shaped tiles have tin-opacified glazes, but most glazes are translucent. The tiles
were subdivided into visual types based upon shape, technique, motif, and color. Typically four–six tiles of each type
were analyzed by inductively coupled plasma spectrometry. Each type of star tile can be matched compositionally to
a single cross type in terms of major and trace elements. Each star-cross pair forms a compositional group, which can
be distinguished from other star-cross groups and from the monochrome tiles. Each group is distinguished in terms
of decorative style, decorative technique, body recipe (clay:glass:quartz), and the elemental composition of the clay
used. The compositional groups represent individual commissions, as tiles were ordered for different rooms in the
palace. The differences in style, technique, and technology among the groups suggest that they were produced by
more than one group of tile makers. Archaeological evidence suggests that some, perhaps all, of the tiles were made
in the vicinity of Kubad-Âbâd. However, at least one tile group has a very different body composition and was made
using a calcareous clay, whereas the others were made using kaolinitic clays. This group may have been imported
