Analytical studies leading to the identification of the pigments used in the Pīr-i Hamza Sabzpūsh Tomb in Abarqū, Iran: a reappraisal
Keywords:wall painting, μ-Raman, μ-XRF, Pīr-i Hamza Sabzpūsh tomb, huntite
This paper presents the outcomes of a restoration project started from 2009 and finalized in 2011 at the Pīr-i Hamza Sabzpūsh tomb of Abarqū, central Iran. The project comprised of analytical studies and restoration works on the architectural decorations consisting of wall paintings and polychrome stuccoworks. Micro-Raman spectroscopy (μ-Raman) and micro X-ray fluorescence (μ-XRF) micro-analysis were used to compare the chemical and mineralogical composition of the pigments used in the wall paintings and the stuccoworks of the mihrab. The results showed that atacamite, huntite and ultramarine were green, white and blue pigments used on both wall paintings and the stuccoworks of the mihrab. Furthermore, while red lead was used as red pigment on the mihrab, the red pigment of the wall paintings was identified to be red hematite. Apart from the difference between the red pigments used on the mihrab and the wall paintings, the different trace elements associated with other paints established different sources of supplying pigments used in the decorations. It is also shown that red lead was partially blackened likely due to the action of air pollutants. Moreover, an omitted part of an inscription of the mihrab was discovered during restoration works that contributed to re-date the stuccoworks to the second half of the 12th century. Finally, rejecting the current assumptions, which attribute the wall paintings to the 14th century, it was proved that the wall paintings were the first decorations of the tomb created prior to the second half of the 12th century. The current work contains also a corrigendum to our previous study published on the decorations of the tomb.