A STUDY OF ANCIENT CHINESE PORCELAIN WARES OF THE SONG‐YUAN DYNASTIES FROM CIZHOU AND DING KILNS WITH ENERGY DISPERSIVE X‐RAY FLUORESCENCE*

Multi‐variable statistical analysis based on energy dispersive X‐ray fluorescence measurements on both porcelain body and glaze is employed to give clear and consistent classification of porcelain sherds from northern China of different styles from the Song‐Yuan dynasties (Ding and Cizhou styles), and also from the Sui‐Tang dynasties (Xing style). However, the observed separation is less clear for Cizhou style sherds produced at neighbouring kiln sites. Imitation Ding porcelain samples produced by ancient Cizhou potters are also analysed.     

THE COMPLEMENTARY USE OF NEUTRONS AND X‐RAYS FOR THE NON‐DESTRUCTIVE INVESTIGATION OF ARCHAEOLOGICAL OBJECTS FROM SWISS COLLECTIONS*

This paper shows the possibilities offered by the combined use of non‐destructive neutron and X‐ray beams in archaeological research on metallic finds. The following five artefacts from Swiss excavations were submitted to investigation, each with dedicated aims: a Roman sword, a Roman dagger, an Iron Age bucket, Iron Age spearheads and a Roman finger ring. The images obtained with both methods—neutrons and X‐rays—are discussed in length in this paper. The investigations took place at the Paul Scherrer Institute and the archaeologists who studied the objects come from the Universities of Lausanne and Zurich.     

THE APPLICATION OF A PORTABLE X‐RAY FLUORESCENCE SPECTROMETER TO THE ON‐SITE ANALYSIS OF GLASS VESSEL FRAGMENTS FROM SOUTHERN THAILAND*

Ancient glass vessel fragments belonging to the seventh to ninth centuries ad , from the Ko Kho Khao, Laem Pho and Khuan Lukpad sites in southern Thailand, were studied. The glass vessel fragment samples are a collection belonging to the Department of Archaeology, the 15th Regional Office of Fine Arts of Thailand. The chemical compositions of the glasses were analysed using a modified portable energy‐dispersive X‐ray fluorescence spectrometer (OURSTEX 100FA‐II) by the introduction of a MOXTEK^® AP3.3 polymer window (5 mm²?) to the KETEK silicon drift detector for the measurement of light elements. The non‐destructive analysis was performed at the National Museum, Phuket, in Thailand. It is shown that the glass chemical compositions belong to mineral and plant‐ash based soda–lime–silicate glass. The origins of the glass artefacts are discussed in terms of raw materials and glass decoration, and compared with previously reported similar typological glasses from sites in the port city of Rāya and the Monastery of Wadi al‐Tur in Egypt.     

ANALCIME CRYSTALLIZATION AND COMPOSITIONAL PROFILES—COMPARING APPROACHES TO DETECT POST‐DEPOSITIONAL ALTERATIONS IN ARCHAEOLOGICAL POTTERY*

The approaches of comparative studies and profile measurements, often used in order to detect post‐depositional alterations of ceramics, have been applied simultaneously to two sets of Roman pottery, both of which include altered individuals. As analytical techniques, Neutron Activation Analysis and X‐Ray Diffraction have been used. Both approaches lead to substantially different results. This shows that they detect different levels of alteration and should complement each other rather than being used exclusively. For the special process of a glassy phase decomposition followed by a crystallization of the Na‐zeolite analcime, the results suggest that it changes high‐fired calcareous pottery rapidly, and so fundamentally that the results of various archaeometric techniques can be severely disturbed.     

THE EFFECTS OF CORROSION AND CONSERVATION TREATMENTS ON NON‐DESTRUCTIVE NEUTRON DIFFRACTION ANALYSIS OF ARCHAEOLOGICAL COPPER ALLOYS: PRELIMINARY RESULTS*

Analysis of residual stress in archaeological copper alloy artefacts by neutron diffraction has considerable potential for the investigation of early fabrication processes. However, residual stresses in metals are known to relax due to conditions similar to those encountered during burial, corrosion and conservation. In this pilot study, we investigate the effects of corrosion and conservation on a small group of replica copper ingots. Although corrosion and light cleaning do indeed cause some relaxation of stresses in the metal, corrosion having the most significant effect, the basic patterns and major features of the stress profiles may still be seen.     

A TECHNOLOGICAL EXAMINATION OF NINTH–TENTH CENTURY AD ABBASID BLUE‐AND‐WHITE WARE FROM IRAQ,AND ITS COMPARISON WITH EIGHTH CENTURY AD CHINESE BLUE‐AND‐WHITE SANCAI WARE*

Eight sherds of ninth–tenth century ad Abbaesid blue‐and‐white glazed earthenware, excavated in 1931 at Hira in western Iraq, were analysed using, variously, quantitative wavelength‐dispersive spectrometry (WDS) and energy‐dispersive spectrometry (EDS) in association with scanning electron microscopes (SEM), and semi‐quantitative X‐ray fluorescence spectrometry (XRF). In order to compare the compositions of the cobalt pigments used, the glazes of seven complete vessels of eighth century ad Chinese Tang blue‐and‐white sancai were also analysed semi‐quantitatively using XRF. The Abbasid wares were shown to have used traditional Mesopotamian alkali–lime glazes applied to calcareous clay bodies. Half the glazes examined were opacified with tin oxide. Three types of blue decoration (i.e., raised; spreading; and flat, non‐spreading) were produced using a variety of formulations, including a mixture of cobalt pigment with lead oxide. The sources of the ores used for the cobalt pigments have not been identified. However, the analytical data showed that the cobalt ore used for the Abbasid blue‐and‐white ware could be distinguished from that used for the Tang blue‐and‐white sancai by its higher iron content and by the presence of a significant amount of zinc. The use of cobalt‐blue decoration on the ninth–tenth century ad Abbasid ware was anticipated in China by eighth century ad Tang blue‐and‐white sancai wares. However, whether its introduction by the Abbasid potters should be seen as an independent invention that followed the introduction of tin‐opacified glazes in Iraq, or whether it was influenced in some way by Chinese originals, is still unresolved.     

CHARACTERIZATION OF RED‐COLOURED SLIPS (ALMAGRA) ON ISLAMIC CERAMICS IN MUSLIM SPAIN*

Small objects found in Islamic (eleventh‐century) kilns excavated in Zaragoza (Spain) were studied to determine the nature of the red coating of almagra pottery. Ceramics with almagra decoration were completely coated with a glossy deep‐red layer, a slip, applied to the body before firing. Chemical and mineralogical studies were carried out, together with analysis of a surface treatment with organic compounds. The results of this study confirm that almagra ceramics were produced by means of a specific and elaborate process (slip preparation, firing and wax application), demonstrating the introduction of this slip into local production during the Islamic period.