BYZANTINE OPAQUE RED GLASS TESSERAE FROM BEIT SHEAN,ISRAEL*

This paper presents the results of analysis of Byzantine opaque red glass tesserae derived from three separate locations in the ancient city of Beit Shean, Israel. Investigation proceeded using reflective light microscopy, energy dispersive X‐ray fluorescence and energy dispersive scanning electron microscopy. The glass matrix of the tesserae was found to be heterogeneous, with many inclusions. Similarities and differences between tesserae from the two mosaics are examined and discussed. Implications for locale of manufacture and production techniques are considered. Comparisons between the three locations led to conclusions about the use of the tunnel as a storage site and the implications of this for future research on mosaics.     

THE RED INK OF THE DEAD SEA SCROLLS

The red ink on four fragments of the Dead Sea Scrolls was analysed by X-ray fluorescence and X-ray diffraction. The red pigment was identified as mercury sulfide (HgS), cinnabar. The significant archaeological and historical aspects of this finding are discussed.     

MAGNETIC SUSCEPTIBILITY THICKNESS CORRECTIONS FOR SMALL ARTEFACTS AND COMMENTS ON THE EFFECTS OF‘BACKGROUND’MATERIALS*

Correction factors for magnetic susceptibility measurements on thin (<c. 50 mm thick > artefacts have been determined experimentally for a KT‐5 Exploranium G S. instrument using prepared blocks of Whin Sill dolerite. The cor rection factor is large (> 1.4) for samples less than 10mm thick, and reduces to 1 01 for samples of 50mm thickness. Measurements on thin samples can also be affected by the backing or substrate material on which they are measured. ‘Background’material, for example, soil or plaster, can contribute significantly to recorded measurements on artefacts, particularly for thin artefacts with low susceptibilities     

MINERALOGY OF BOHEMIAN GREEN EARTH PIGMENT AND ITS MICROANALYTICAL EVIDENCE IN HISTORICAL PAINTINGS

While the most famous historical green earth deposits in Italy and Cyprus were exceptionally rich in celadonite, the deposits near Kadaň, Czech Republic, consisted of thin Fe‐rich celadonite impregnations accompanied by interstratified celadonite/smectite. In superimposed tuffs, smectites become prevalent and their colour changes from forest to olive green. Powder X‐ray microdiffraction and infrared microspectroscopy permit us to distinguish between green earth minerals in microsamples taken from works of art. The Ti contents and the Fe/Mg ratios help to indicate the presence of Bohemian green earth from Kadaň. We found this material in local 18th‐century works of art and also in paintings by Anton Kern (1709–47).     

MINERO‐PETROGRAPHIC STUDY OF COOKING WARE AND POMPEIAN RED WARE (ROSSO POMPEIANO) FROM CUMA (SOUTHERN ITALY)

Excavations carried out in Cuma by the Centre Jean Bérard archaeologists have uncovered a large quantity of pottery. This study is focused on cooking ware and on internal red‐slip cookware, also known as Pompeian Red Ware (Rosso Pompeiano), dated from the first century bc to the first century ad . A comparison with the minero‐petrographic composition of beach sands collected along the Bay of Naples coastline highlights the provenance of the temper from the Somma‐Vesuvius area, marked by leucite‐bearing scoriae and garnet. Petrochemical analyses allow us to distinguish two main groups of pottery characterized by different technological options based on the amount of temper and on the type of clay. X‐ray diffraction and scanning electron microscope data demonstrate improved accuracy in the production of Rosso Pompeiano, especially with regard to firing control, which was in a prevailing oxidizing atmosphere and in a narrow thermal range, between about 800 and 900°C.     

DOMUS AUREA,THE ‘SALA DELLE MASCHERE’: CHEMICAL AND SPECTROSCOPIC INVESTIGATIONS ON THE FRESCO PAINTINGS

In this paper, data collected from the wall fresco paintings of room 114, called the ‘Sala delle maschere’, of the Domus Aurea in Rome is analysed. The chemical composition of the efflorescence is investigated by infrared spectroscopy. The colour palette is determined by means of EDXRF, Raman spectroscopy and visible reflectance spectroscopy. EDXRF has allowed an extensive mapping of the elements present in the pigments and plaster; whilst in‐situ Raman spectroscopy has been determinant for attributing the molecular composition of the pigments in a number of doubtful cases. Most pigments identified are typical of Imperial Roman fresco paintings (first to fourth centuries AD) ( Ward‐Perkins 1981 ); more interestingly, we found evidence of fragments painted with Egyptian blue, which was normally used mostly in official rooms.     

ROMANO‐EGYPTIAN RED LEAD PIGMENT: A SUBSIDIARY COMMODITY OF SPANISH SILVER MINING AND REFINEMENT*

Samples of red pigment from a group of seven Roman‐period Egyptian mummies, known as red‐shroud mummies, are investigated. Elemental analysis by inductively coupled plasma time‐of‐flight mass spectrometry (ICP–TOFMS) shows that the samples contain mostly Pb (83–92% by weight), along with 0.2–2.0% Sn. All of the samples are found to have similar trace element distributions when normalized to the continental crust, suggesting that they share a common geological origin. Lead isotope ratios are found to match the mixed lead sources typically associated with Rio Tinto, Spain – a site extensively mined for silver during the first century ad . Raman microspectroscopy identifies the major phase of each sample to be red lead (Pb₃O₄) with a minor phase of lead tin oxide (Pb₂SnO₄). Lead tin oxide does not occur naturally, and its incidental occurrence within the sample indicates that the material was heated under oxidative conditions at temperatures in excess of 650°C. In archaeological contexts, the high‐temperature oxidative treatment of lead is typically associated with metallurgical refinement processes such as cupellation. Based on this evidence, it is argued that the pigment was produced out of litharge associated with silver cupellation at the Rio Tinto site.     

A SPECTROSCOPIC INVESTIGATION OF PIGMENT AND CERAMIC SAMPLES FROM COPÁN,HONDURAS*

A combination of micro‐Raman spectroscopy, micro‐infrared spectroscopy and SEM–EDX was employed to characterize decorative pigments on Classic Maya ceramics from Copán, Honduras. Variation in red paint mixtures was correlated with changing ceramic types and improvements in process and firing techniques. We have confirmed the use of specular hematite on Coner ceramics by the difference in intensities of Raman bands. Different compositions of brown paint were correlated with imported and local wares. The carbon‐iron composition of the ceramic type, Surlo Brown, was confirmed. By combining micro‐Raman analysis with micro‐ATR infrared and SEM–EDX, we have achieved a more comprehensive characterization of the paint mixtures. These spectroscopic techniques can be used non‐destructively on raw samples as a rapid confirmation of ceramic type.     

CHEMICAL AND MINERALOGICAL ANALYSES OF GALLO-ROMAN WALL PAINTING FROM DIETIKON,SWITZERLAND

Around 90 samples of Roman wall painting dating from the first to the third century AD were analysed using different analytical techniques: X-ray diffraction, X-ray fluorescence, infrared spectrometry, scanning electron microscopy, energy dispersive spectrometry, optical microscopy and physico-chemical tests. The identified pigments are: ash, calcite, carbon black, celadonite, cinnabar, Egyptian Blue, glauconite, goethite, hematite and red lead. Pigment mixtures were used to get other colours such as brown, pink or purple. Three types of plaster were used: a first, and most dominant, with river sand, a second with crushed tile for damp places and a third, to which cinnabar was exclusively applied, was prepared with crushed calcite crystals.     

A WATER ABSORPTION ANALYSIS OF NABATEAN,NORTH AFRICAN AND OTHER CLAY LAMP FABRICS UNEARTHED AT THE RED SEA PORT OF ROMAN AILA (AQABA,JORDAN)*

A water absorption analysis was conducted on 103 clay lamp samples to determine whether the fabrics of this pottery type are porous. If so, this would lend further support to the long‐standing assumption that lamp makers coated their lighting vessels with slip—not just for decorative purposes, but as a means of preventing oil seepage of the fuel chamber. The samples were excavated at the Red Sea port of Roman Aila (modern Aqaba, Jordan) and belong to 10 different types originating from Arabia, Palestine, Egypt, Tunisia and Gaul. The results of the experiment reveal that clay lamp fabrics are porous, and comparatively more so than a reference group of non‐lamp pottery from Pella (Jordan). Petrographic thin‐section analysis of select fabrics confirms the presence of pores, cracks and propagating veins indicative of thermal stress resulting from repeated lamp use. Meandering veins identified in a nozzle fragment were created by the diffusion of vapours, probably originating from the burning lamp oil itself. Ancient lamp makers understood that, given its direct exposure to the extreme temperature of the flame, the nozzle was particularly vulnerable to breakage as a result of thermal shock. A porous lamp fabric, however, helped limit crack propagation, allowing the nozzle and the lamp body to expand and contract to avoid breakage.