Early Islamic pigments used at the Masjid-i Jame of Fahraj, Iran: a possible use of black plattnerite

Based on micro-Raman spectroscopy (μ-Raman), micro X-ray fluorescence spectrometry (μ-XRF), X-ray diffractometry (XRD) and optical microscopy, this paper presents the results of our analytical studies on the early Islamic pigments used in the Masjid-i Jame of Fahraj, central Iran. Our investigations showed that ultramarine blue and haematite were used as blue and red pigments, respectively. Moreover, huntite was identified as white pigment with which whewellite was associated as a degradation product. Interestingly, the black paint was identified to be mainly composed of black plattnerite mixed with mimetite, hydromorphite and galena. Our geological survey at the Darreh Zanjir mine, located 35 km west of Fahraj, suggested this mine to be a possible source for supplying the black plattnerite. Accordingly, black plattnerite is suggested to be most probably used as a pigment and not to have formed as a degradation product of lead-based pigments.