Della Robbia blue glaze: micro-Raman temperature study and X-ray fluorescence spectroscopy characterization

• Published in: Journal of Raman spectroscopy Vol. 41; no. 4; pp. 469 - 472
• Main Authors: Sendova, M., Kaiser, B., Scalera, M., Zhelyaskov, V.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-04-2010
• Subjects: Della Robbia; Exhibitions; Fluorescence; Glazes; lazurite; majolica glazes; micro-Raman spectroscopy; Ores; Pigments; Spectroscopy; Terracotta; X-rays; XRF
• ISSN: 0377-0486; 1097-4555
• DOI: 10.1002/jrs.2459

Micro‐Raman temperature study and X‐ray fluorescence (XRF) spectroscopy were used for characterization of the blue glaze on Saint John the Baptist—majolica terracotta relief attributed to Andrea Della Robbia and Saint John the Baptist with Cross—majolica terracotta statue attributed to Giovanni Della Robbia. Both objects are on permanent exhibition in the John and Mable Ringling Museum of Art in Sarasota, FL. This study proves that the detection of the 548 cm−1 Raman band alone cannot serve as evidence for presence of lazurite crystallites in the pigment in the glaze. It was established that the famous Della Robbia blue is due to the combined effect of CoNiCuZn atoms and S3− ions embedded in a lead silicate matrix. It is proposed that the Della Robbia family used Co‐containing sulfide ores as a source for manufacturing their blue pigments. Copyright © 2009 John Wiley & Sons, Ltd.
Detection of the 548 cm−1 Raman band alone may not justify the presence of lazurite crystallites in the pigment of a glaze. The 548 cm−1 Raman band is indicative of the presence of the S3− chromophore but not of the composition of the matrix in which it is embedded. Based on the micro‐Raman temperature study and XRF analysis, we can conclude that the famous Della Robbia blue is due to the combined effect of Co–Ni–Cu–Zn atoms and S3− ions embedded in a lead silicate matrix.