Understanding the Mineralogical Composition of Ancient Greek Pottery through Raman Microprobe Spectroscopy

Abstract

Mineralogical studies using Raman microprobe spectroscopy and high-magnification optical spectroscopy were performed on sherds of pottery vessels that were used as cooking pots and water jars in Hellenistic Greece (third and second century BC). Of specific interest was the mineralogical identification of the so-called inclusions, which are phases that morphologically stand out from the fired clay matrix and result from the presence of inorganic temper in the original paste mixture. The sizes of mono- and polymineralic inclusions in the sherds range from 5 μm to 2 mm. The combined use of Raman microprobe spectroscopy and incident-light optical microscopy permits identification of specific minerals (such as quartz, albite, calcite, hematite, anhydrite, epidote, rutile, anatase, and apatite) in various different types of inclusions and then visual evaluation of the abundance of those minerals in each sample. The application of our nondestructive analytical approach is documented on a set of four sherds (each on the order of several cm2) from excavations of the ancient Agora of Athens. The information on the mineralogy obtained via Raman spectroscopy can shed light on the provenance of the raw materials and firing conditions of the pottery and thus aids archeologists with their historical interpretations.

Circumstellar aluminum oxide and silicon carbide in interplanetary dust particles

“…These features suggest that the IDP Tiberius may have originally been dominated by layer lattice silicates that were subsequently heated and dehydrated. The Raman spectra of some heated phyllosilicates do not have any O-H bands, yet are otherwise reminiscent of their original structure, i.e., the characteristic signatures for the di-octahedral and tri-octahedral phyllosilicate structures are preserved after the heating event, even though the peaks become wider (Wopenka et al, 2002). The carbonaceous peaks in Tiberius at $1350 and $1600 Dcm À1 (Fig.…”

Identification of black pigments on prehistoric Southwest American potsherds by infrared and Raman microscopy

“…A more thorough analysis of ceramic thin sections by Raman microscopy could potentially indicate the nature of the original raw materials, including clays, tempers, and pigment phases, as well as the firing temperatures and atmospheres employed in the production of these pots [29,30]. This possibility is greatly enhanced if Raman analysis is used in conjunction with XRD and SEM-EDX [17].…”

“…These have included the identification and characterisation of inclusions [29,30], mineral pigments [10e12], and vitreous glazes [13,18,19] from ancient ceramics, faience, celadons, and porcelains. Raman spectroscopic studies of well-crystalline graphitic carbon as well as structurally disordered carbonaceous materials, commonly called ''carbon blacks'', have also been published [3,26,28], and it has been possible to identify black graphitic as well as mineral pigments on prehistoric Chinese pottery [32].…”

Raman microscopy in archaeological science

“…Raman microscopy has also been used to perform spectrographic petrography of mineral inclusions in the fabric of unprepared ceramic sherds [150,151]. Petrography is used routinely in the analysis of archaeological ceramics to identify and quantify the mineral component of the clay fabric in order to suggest a provenience for the artefact or to investigate its method of manufacture.…”

“…In their analyses of unprepared sherds of 3rd-2nd century B.C. domestic wares collected from the Agora in Athens, Wopenka et al [150] have utilised the chemical specificity of the Raman technique to identify the various types of inclusion and then semi-quantify those types based on a visual tally of the different forms. The use of spectral libraries simplifies the application of the technique so that little operator training is required; this, combined with the use of unprepared sherds, makes the process of identification extremely rapid.…”