Characterization of a Jian-like sherd with the optical microscope, confocal Raman, wavelength-dispersive X-ray fluorescence, and portable XRF spectrometers

Abstract

The ceramic masterpieces that belong to the private collections and art galleries are rarely studied with analytical instruments to define the authenticity, provenance, and characteristics of the materials because the scientific investigations are required to be solely noninvasive for characterizing the unfractured genuine objects. A monographic program, Blue Print, which was initiated by a German cultural heritage foundation, Art & Science Endowment Trust (ASET) Stiftung, aims at developing on-site research protocols for systematic research investigations on the fragmentary samples, with and without verifiable archeological contexts. For that reason, a combination of analytical techniques was carried out on a Jian-like sherd, which was assumed to be produced either as a genuine artifact between the 11th and late 14th centuries ad or as a Qing Dynasty copy (1644-1911 ad). Before slicing the sherd, confocal Raman microscopy was used to define the red glaze signature and the crystals formed on the glazed surface, whereas portable X-ray fluorescence (XRF) (pXRF) was used to define the composition of the glaze and body. Afterward, the sherd was cut and polished for the characterization with a zoom microscope, wavelength-dispersive XRF (WD-XRF), and Raman. The macroscopic examination revealed the presence of a glassy black colored interface layer, which was detected between the body and red glaze. The composition of the red glaze was determined with XRF and Raman spectrometers, and the presence of cadmium sulfoselenide (CdSxSe1-x, 0 <= x <= 1) with a high amount of zirconium (WD-XRF: 2.20 wt.%, pXRF: 1.55-wt.% ZrO2) was found. Additionally, Raman measurements evidenced the presence of epsilon-hematite crystals formed on the blackened red glazed surface. Unlike the glaze composition, the elemental content of the body is almost the same (Al2O3: 25.7 wt.%, Fe2O3: 8.19 wt.%, K2O: 2.54 wt.%) with the genuine Jian wares already documented by artistic and scientific examinations.