Study of colorants materials on the decoration patterns on the north and southeast porches of Gonbad-e Soltanieh

Colorful decorations and wall paintings are one of the most important and widely used decorating methods applied in the construction of Gonbad-e Soltanieh. Understanding the type of colors and how these paintings and decorations were applied can be one of the most important discussions in knowing more and better about this building and the techniques and paints common in ancient times.The mausoleum of Oljaytu was constructed in 1302–12 in the city of Soltaniyeh, the capital of the Ilkhanid dynasty, which was founded by the Mongols. Situated in the province of Zanjan, Soltanieh is one of the outstanding examples of the achievements of Persian architecture and a key monument in the development of its Islamic architecture. The octagonal building is crowned with a 50 m tall dome covered in turquoise-blue faience and surrounded by eight slender minarets. Therefore, the present study aims to study how the ground was prepared for the implementation of colorful decorations and paintings, as well as what type of colors was used to reach a comprehensive knowledge of the techniques applied by Ilkhanid painters. for the Study of colorants materials on the decoration patterns on the north and southeast porches of Gonbad-e Soltanieh the Scanning Electron Microscopy (SEM) analysis is used to investigate the order of layers and plastering and also, the X-ray diffraction (XRD) analysis and more chemical methods are used to study the type of green, blue, yellow, red, white and black colors. Scanning Electron Microscopy analysis showed the type of plastering and the order of the painting layers well. Also, X-ray diffraction analysis and more chemical analyses identified the colors of malachite green, colored green, azurite blue, red ochre, yellow ochre, anhydride white and carbon black.