With regard to the dry climatic conditions of Iran, cob and gypsum mortars were used in architectural arrays of many regions of Iran, to create the scratch coat (Arriccio) and fine coat (Intonaco) in the historical periods. The thickness of the fine coat was often very low (one-two mm). In this regard, one of the examples is the City of Yazd. One of the buildings made in the eighth century (Islamic calendar) with the mentioned properties in its scratch and fine coats in architectural arrays is the mausoleum of Rokn al-Din in Yazd (1946), which has several architectural arrays, such as: embossed gypsum, mold, painting inscriptions, decorative paintings, gilding arrays and tiling. The most important issue observed in the arrays of this type of buildings is when the straws and vegetable fibers found in cob are consumed by termites, which is recognized as one of the common damages to the buildings in the country center. This phenomenon leads to loss of coherence in the scratch coat, turning it into a weak powder. This damage to the scratch coat is associated with detachment of the underlying layers in the architectural array. There is an extremely thin layer of fine coat, which is completely detached from many parts of the underlying layer. In such conditions, other array holders are gypsum and gilding arrays and wall paintings. In general, it is significantly difficult to maintain this type of architectural arrays. One of the issues that makes restoration more difficult and limits the use of materials and methods to restore a building, is the white background of architectural arrays in these buildings, which makes it impossible to use any strengthening method in these buildings since it leads to the formation of a yellow and dark color on a white background. In addition, filling the empty space behind the gypsum fine coat (without considering the fact that this layer is significantly thin) leads to the separation and collapse of the fine coat and the implemented arrays on the layer (with regard to the gravitational force of the earth). The thin gypsum layer, which is similar to egg shell and is separated from the scratch coat, can be crushed with minimum pressure of the hand. Moreover, the significantly weak attachment of many mold gypsum arrays to the fine coat, the smallest collision, and vibration in that area leads to the separation and collapse of the decorative layer. To eliminate these problems, the soil in the empty space between the fine coat and support was cleaned at first, followed by fixing the upper and lower surface of the fine coat. The sample was created to select the proper material and method, at the end of which the following material and method were selected: fixing the surface with the solution of 6% Acryloid B-72 in ethanol and injecting the mentioned solution to the back of the fine coat. In the next stage, a cavity with the depth of about eight cm was created in parts of the support that experienced breaking or collapsing (brick wall or ceiling). It should be noted that the diameter of the cavity was small on the surface of the support (about two cm), and the more the depth increased, the more the cavity diameter was enlarged. The next phase involved the injection and implementation of gypsum mortar to the lower layers. To this end, the local gypsum of Yazd and eremurus powder were exploited. Injection of the mortar will take a relatively long time and will be carried out in several stages. In each stage, a small amount of mortar is injected into the back of the fine coat and inside the cavity made in the support layer. After each injection phase, two hours is required for complete hardening of gypsum and initiation of the next injection operation. The cavities, along with 10 cm from around the cavity and between the scratch and fine coats, are completely filled with gypsum, which results in the attachment of layers to each other. In addition, this mortar acts like a nail, attaching the gypsum fine coat to the lower layers. In this experiment, the described strengthening method was called gypsum nail. Implementation of gypsum nails with relatively specific distances from each other (50-100 cm) will lead to the fixing of the fine coat and layers attached to its surface without putting pressure on the thin gypsum fine coat.

Temple of Verjuy or Mehr Temple is one of the particular monuments in the type of regional architecture, in the slope of Sahand volcano; has been located in Verjuy village in the suburbs of the Maragheh city, East Azerbaijan province, Iran. The Verjuy researchers believe that this building belongs to the Mithraism religion which is an Iranian ancient religion (248 BCE-224 CE). But, new excavation around the temple demonstrated that this building is a part of underground rocky architecture with an unclear date and history. Underground Verjuy temple has seven spaces with a number of holes which are connected to each other. According to the literature, the temple was a worshiping place before Islam, but since then, the evidence show that it was used as a mosque. The architectural decorations of the temple have not been taken into consideration and in general, a lot of references, repeat the first information related to the history, usage and stone carving of this temple. As the specific architectural decorations of this monument have not yet been scientifically studied, the exploring variety of architectural decorations as well as the characterization of materials used for making the decorations of this building would be one of the main objectives of this research. Based on the results obtained, the main decorations of temple are including: carving of Islamic Arabesque and Quranic inscriptions as well as Moqarnas decoration inside the dome of the main space of the building. The results also showed the application of mortar on architectural decoration as a plaster inside the building and also on the surface of Moqarnas as a very thin layer in Islamic era. Moreover, the field work (redrawing the plan of temple and describe of architectural spaces as a documentation of architectural decorations with photography) and sampling of plaster along with XRPD, XRF and thin section petrography analysis were done. The results of this research show that, except for stone decoration, there is another decoration with lime base mortar in cover of Muqarnas work and some other places of the building, that this new finding is reported for the first time. This finding showed the application of the building during different periods and it is possible to attribute the earliest works and shreds of evidence of the use of the original dome in its new use in the Islamic era, to the Ilkhanid period.

The companion of different materials in architectural decorations of Iran, during the Islamic era, in many cases has opened up new art styles and techniques and changed the aesthetic look of the cultures that carry this phenomenon. The accompaniment of brick, plaster and glaze decorations is one of the fascinating changes in the history of art of Iranian architectural decorations that its history of invention has remained somewhat obscure. Meanwhile, the initial idea of using tiles in the decorations of Iranian architecture in the Islamic era remains largely unknown. Tile is a type of architectural decoration that may be originated from ancient Iran, and therefore, little information is available about the manufacturing and execution techniques and specimens of tile works from the early centuries of the Islamic era. This aim of this work was to distinguish between the tile and the glazed-brick. From the view-point of the researcher, when the thickness of the glazed-ceramic exceeds from its width, the work becomes glazed-brick, while the width of the glazed-ceramic become greater than its thickness, it will be a tile. The main purpose of this research was to obtain the information on the oldest tiles of the Islamic period in Iran, which could be found as the glazed-ceramic in the architectural design Khajeh Atabak in Kerman. In order to achieve the aims of this research, the study of written sources and the field studies were carried out simultaneously, to characterize the tile works in Iranian architectural decorations, especially at the tomb of Khajeh Atabak in Kerman. On the basis of the results obtained, it could be said that unfortunately from the Islamic period in Iran till the 11th century AD., no dated tiles have been left. Many of the tiles with no written date on them have been dated by researchers regardless the manufacturing technology, and only based on the tiles appearance and archaeological characteristics.  These dating studies have not been performed based on the laboratory studies and they were actually done with speculation, so are not scientifically acceptable. For example, for decades it was thought that the oldest tiles in Iranian architecture belong to the Qazvin Jame-Mosque, while as a result of field studies realized in this research, it was found that there is no antique tile in this monument, where the color of the painting was mistakenly recognized as tile. Donald Wilber reported this error for the first time, and over the several decades, all the researchers repeated the same error without careful scrutiny. Anyway, the tile samples of five monuments with a collection of tiles or with one single tile were identified as the oldest tiles of the Islamic period in Iran. One of the main results of this research is to identify the use of fractured pieces of glazed pottery in architectural decorations, where some researchers have identified these works as the tiles. In these cases, both sides of the pieces of potteries have glaze and the body is very thin and delicate along with the arches and curves. Moreover, in some cases the edges of the pottery container can also be seen. Achieving this result reinforces this hypothesis that using the broken pottery container may have formed the first idea for tiles construction.

The pastiglia technique has been widely used as the preparation layer for gilding decoration in Iran during the Safavid period. Generally, the purpose of pastiglia is to create a prominent surface for the gilding array. The main research issue is the lack of technical and structural knowledge of the layered arrays of the two churches under study. Lack of sufficient research and resources on the technical and structural knowledge of Pastiglia and gilding decorations in the Armenian churches of Julfa, and also the existence of technical ambiguities and lack of clarity on the origin of art of Isfahan Armenians, such as architectural decorations and especially Pastiglia art, are the necessities of doing this research. The present study provides a technological overview towards the pastiglia employed in the gilding decoration at the Bethlehem Church and Vank Cathedral, as two important Armenian monuments from the Safavid era at New Julfa in Isfahan, using pyrolysis–gas chromatography-mass spectrometry (Py-GC-MS), gas chromatography-mass spectrometry (GC/MS), X-ray diffractometry (XRD) and scanning electron microscope coupled with energy dispersive X-ray spectrometry (SEM-EDX). GC/MS and Py-GC-MS used for the characterization of organic materials of samples and XRD and SEM-EDX used for the characterization of inorganic materials of samples. The analytical data show that animal glue was used as a binding medium of pastiglia while linseed oil was probably employed as the mordant agent in the gilding decorations; Furthermore, linseed oil was used as a varnish layer on the gilding decorations of Vank cathedral. Also, the inorganic part of the pastiglia substrate showed to have been composed of gypsum and an iron-rich clay. These results are discussed in the larger context of the pastiglia technique in other contemporary historical monuments in Isfahan. It can be said that this present research is looking for structural and technical differences and affinities of these decorations in Isfahan Armenian and Islamic buildings at Safavid era.
 

The wall paintings of Qazvin Chehelsotoun Mansion include two periods in the early Safavid period and one period in the Qajar period. This topic has received little attention in the field of structural studies and stylistics. Investigating these decorations in order to understand the evolution of this art and considering the temporal precedence over other murals in the Safavid period seems necessary. The city of Qazvin is located in the northern part of Iran and west of its capital. Qazvin has been the capital city of Iran for more than half a century in the Safavid era.Today only a few important monuments of that era remained. That is why they all need special attention to identify, maintain and introduce.Among these monuments, the Chehelsotoun mansion is very important because of the remaining of the early Safavid murals.Pastiglia and gilding is one of the most complex and special methods of surface decoration in Islamic architecture of Iran, the flourishing of which should be sought in the Safavid period; This architectural array, which is a combination of organic materials as well as metallic and non-metallic minerals, was processed and executed during a special process. In order to properly protect the work and also to retrieve the technical information contained in it, as well as to obtain the technical information of this type of architectural arrangement in Safavid Iran, its artistic and technical recognition in Qazvin Chehelsotoun as one of the most important buildings in the capital. Safavidism becomes important and necessary. From the first capital of the Safavid period (in Tabriz) there is no layered and gilded array and Qazvin before Isfahan was considered and appropriate measures have been taken to create architectural arrays. The present study has studied the structure of layered and gilded arrays in the two Safavid periods (Shah Tahmaseb period and Shah Abbas period) in Qazvin Chehelsotoun. This research has been done with a laboratory approach with the aim of analyzing and understanding the structure of different parts of these arrays, including the organic and inorganic structure of the pastiglia layer, as well as the golden layer used on the pastiglia layer, called gilding. In this regard, sampling was done from the layer of pastiglia and gilding related to Shah Tahmaseb period and also the layer related to Shah Abbas Safavid period, which was evaluated using analyzes (SEM-EDS, FT-IR, GC-MS) and These samples were compared. The result of EDS analysis from the surface of the metal layer indicates high purity gold. Also, the mineral part of the pastiglia layer is composed of gypsum and a type of soil with a high percentage of iron (Hormuz or Armenian mud). Examination of SEM images on the samples showed the presence of residues of organic matter used in pastiglia and gold-plated arrays. Examination of the samples with GC-MS indicates the use of vegetable oils, which due to the significant amount of eighteen carbon compounds and their oxides, it can be attributed to flaxseed oil as a gold leaf adhesive in pastiglia layer arrays and Gilding has been used.