Raman identification of glassy silicates used in ceramics, glass and jewellery: a tentative differentiation guide

Abstract

As an optical method, Raman microspectroscopy offers a great advantage over most other techniques in that it can be performed without any contact with the studied artefact, both at the laboratory using highresolution, large spectral window instruments, and on site using medium resolution, portable instruments. Six years of experience on various materials has enabled us to propose a tentative guide to identify different types of glassy silicates and to classify them as a function of their composition. In previous papers, different families were recognised empirically using a limited set of samples and the relationship between the peak area ratio (A 500 /A 1000 ) of the Si-O bending (∼500 cm −1 ) and stretching (i.e. ∼1000 cm −1 ) envelopes, and the different components of the latter peak were established for porcelain glazes. In this paper, we extend the procedure to a larger set of samples (30 representative samples with known compositions selected from hundreds of spectra). Additional relationships between the origin of the material, the Raman parameters and the glass composition (fluxing oxide content, ionicity ratio, etc.) are discussed. Finally we propose different procedures with different degrees of complexity (from two to multivariate treatment) to identify the glass composition. The method is illustrated with an example, namely, the differentiation between Iznik and Kütahya productions.

Investigation of an enameled glass mosque lamp: a 13th–14th-century Mamluk example or 19th-century European version?

“…4o) enamels. The presence of fluxes, such as lead oxide (PbO), in the glass composition modifies the network of SiO 4 tetrahedra, impacting the Raman signature: a broad Si-O stretching band at lower wavelength, around 950-960 cm −1 , has been identified as characteristic of lead-containing glasses [13]. The position of the Si-O stretching band observed in the white, yellow, and green enamels constitutes another indication of these enamels' enrichment in lead oxide, probably more moderate in the white enamel based on the intermediate position of the band.…”

Vibrational spectroscopy for the study of Chilean cultural heritage

“…The IR and Raman analyses confirm the presence of orpiment. In fact, the IR spectrum of the archaeological sample shows the characteristic orpiment bands between 250 and 400 cm −1 due to the νAs-S mode [33][34][35][36][37][38][39]. The Raman spectrum (Fig.…”

Lacquerware Pigment Identification with Fixed and Mobile Raman Microspectrometers: A Potential Technique to Differentiate Original/Fake Artworks

“…Pigments and specific mixtures by which sometimes they were commercialized can be used to trace given periods of production. Therefore identification of specific pigments in artwork can be used for dating purposes, as was already demonstrated for paintings, glass, ceramic or enameled metal objects [1,3,[5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Their presence of certain pigments may indicate a restoration, later embellishment or identify a fake or a modern replica.…”

“…Portable IR instrument determines the media and 785 nm Raman instrument identifies only a limited number of the pigments identified at the laboratory with fixed instruments. Previous lacquerware studies dealt with archaeological artifacts and with Japanese urushi, [16][17][18] th century artifacts [21][22][23][24][25][26][27][28][29][30], mainly using Pyrolysis Gas Chromatography and Mass Spectrometry (Py-GC/MS) but did not concern the pigment palette identification. FT-IR spectroscopy was also used on powdered samples in KBr pellets or specially prepared films [26][27][28][29].…”