Technical studies and conservation of a fragmented painted plaster excavated from the Vigol Sasanian site, Central Iran

Abstract

The study presented here applied various analytical techniques to examine a small fragmented painted gypsum plaster with heart motifs discovered at the Sasanian site of Vigol, Central Iran, to identify the materials used to produce the plaster. The plaster and its paint layer were analysed by X-ray fluorescence, X-ray diffraction, optical microscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy and micro-Raman spectroscopy methods. The results revealed that the plaster layer is made of gypsum with some impurities—mainly soil minerals—with the concentration of these impurities being less at the surface of the plaster. It was also discovered that the heart motifs were painted using minium red lead pigment. As the main damage to the plaster is fragmentation, conservation included joining the fragments and consolidating the surface of the plaster. Finally, a preservation box using transparent polycarbonate plates was designed and manufactured for the display and handling of the newly restored plaster.

Résumé

«Etudes techniques et conservation d'un plâtre peint morcelé provenant des fouilles du site sassanide de Vigol, au Centre de l'Iran»

L'étude présentée ici a appliqué diverses techniques analytiques pour examiner un petit plâtre de gypse morcelé peint orné de motifs de cœurs découvert sur le site sassanide de Vigol, dans le Centre de l'Iran, afin d'identifier les matériaux utilisés pour produire le plâtre. Le plâtre et sa couche picturale ont été analysés par fluorescence des rayons X, diffraction des rayons X, microscopie optique, microscopie électronique à balayage-spectroscopie à rayons X à dispersion d'énergie et micro-spectroscopie Raman. Les résultats ont révélé que la couche de plâtre est constituée de gypse avec quelques impuretés—principalement des minéraux provenant du sol—la concentration de ces impuretés étant moindre à la surface du plâtre. Il a également été découvert que les motifs de cœurs étaient peints à l’aide d’un pigment rouge de minium. La principale altération du plâtre étant le morcellement, le projet de conservation comprenait la réintégration des fragments et la consolidation de la surface du plâtre. Enfin, une boîte de conservation avec des plaques de polycarbonate transparent a été conçue et fabriquée pour la présentation et la manipulation du plâtre nouvellement restauré.

Zusammenfassung

„Technische Studien und Konservierung eines fragmentierten bemalten Gipses aus der sasanidischen Stätte von Vigol, Zentral-Iran“

In der hier vorgestellten Studie wurden verschiedene Analysetechniken angewandt, um ein kleines, bemaltes Gipsfragment mit Herzmotiven, der in der sasanidischen Stätte von Vigol im Zentral-Iran entdeckt wurde, zur Identifikation der bei der Herstellung verwendeten Materialien zu untersuchen. Der Gips und seine Farbschicht wurden mittels Röntgenfluoreszenz, Röntgenbeugung, optischer Mikroskopie, Rasterelektronenmikroskopie, energiedispersiver Röntgenspektroskopie und Mikro-Raman-Spektroskopie analysiert. Die Ergebnisse zeigten, dass die Putzschicht aus Gips mit einigen Verunreinigungen—hauptsächlich Bodenmineralien—besteht, wobei die Konzentration dieser Verunreinigungen an der Oberfläche des Putzes geringer ist. Außerdem wurde festgestellt, dass die Herzmotive mit roten Bleioxid (Mennige) gemalt wurden. Da der Gips hauptsächlich durch Fragmentierung beschädigt wurde, umfasst die Konservierung das Zusammenfügen der Fragmente und die Konsolidierung der Gipsoberfläche. Schließlich wurde eine Konservierungsbox aus transparenten Polycarbonatplatten entworfen und hergestellt, in der der frisch restaurierte Gips ausgestellt und aufbewahrt werden kann.

Resumen

“Estudios técnicos y de conservación de un fragmentado yeso pintado que había sido excavado en el yacimiento sasánida de Vigol, en Irán central”

En el estudio que aquí se presenta, se aplicaron diversas técnicas analíticas para examinar un pequeño yeso fragmentado y pintado con motivos de corazones—descubierto en el yacimiento sasánida de Vigol, en el centro de Irán—con el fin de identificar los materiales utilizados para fabricar el yeso. El yeso y su capa de pintura se analizaron usando métodos de fluorescencia de rayos X, difracción de rayos X, microscopía óptica, microscopía electrónica de barrido-espectroscopía de dispersión de energía de rayos X, y espectroscopía micro-Raman. Los resultados revelaron que la capa de yeso está compuesta por yeso con algunas impurezas -principalmente minerales del suelo-, siendo menor la concentración de estas impurezas en la superficie del yeso. También se descubrió que los motivos de corazones habían sido pintados con pigmento de plomo rojo minio. Como el principal daño del yeso es la fragmentación, la conservación incluyó la unión de los fragmentos y la consolidación de la superficie del yeso. Por último, se diseñó y fabricó una caja para asegurarse de su preservación, incluyendo placas de policarbonato transparente con el fin de facilitar el exponer y manipular el yeso recién restaurado.

摘要

“关于伊朗中部维戈尔萨珊遗迹出土的彩绘石膏碎片的技术研究与保护”

本研究应用多种技术对一小块带有心形图案的彩绘石膏碎片（发现于伊朗中部维戈尔萨珊遗址）进行了分析，以判断制作石膏的材料。研究人员通过 X 射线荧光、X 射线衍射、光学显微镜、扫描电子显微镜-能量色散 X 射线光谱和微拉曼光谱等方法，分析了石膏及其颜料层。结果显示，石膏层是由石膏和一些杂质（主要是土壤矿物）组成。这些杂质在石膏表面的浓度较低。此外，他们还发现了心形图案是用少量铅丹颜料绘制而成。鉴于石膏的主要损伤是碎裂，保护的工作包含了碎片拼接和石膏表面加固。最后，他们设计并生产了一个由透明聚碳酸酯板制成的保护盒，用于新修复完的石膏的展示和拿

Keywords:

• Sasanian painting
• Vigol
• painted plaster
• gypsum
• red lead
• consolidation

Acknowledgements

The authors are grateful to Dr Mohsen Mohammadi Achachlouei (Art University of Isfahan) for his valuable comments and scientific suggestions, Dr Parviz Holakooei (Art University of Isfahan) for performing micro-Raman spectroscopy analyses as well as Dr S. Yahya Hejazi (University of Tehran) for proofreading and editing the English version of the manuscript.

Notes

1 Cf. for example, Janey M. Cronyn, The Elements of Archaeological Conservation (London: Routledge, 1990).

2 See, for example, Philip Ward, The Nature of Conservation: A Race Against Time (Los Angeles: Getty Conservation Institute, 1989); Cronyn, The Elements of Archaeological Conservation; Christian Degrigny, ‘Examination and Conservation of Historical and Archaeological Metal Artefacts: A European Overview’, in Corrosion of Metallic Heritage Artefacts: Investigation, Conservation and Prediction for Long-Term Behaviour, ed. Philippe Dillmann et al. (Cambridge: Woodhead Publishing, 2007), 1–17.

3 See, for example, Elisabeth Pye, ‘Archaeological Conservation: Scientific Practice or Social Process?’, in Conservation Principles, Dilemmas and Uncomfortable Truths, ed. Alison Richmond and Alison Bracker (Oxford: Butterworth-Heinemann, 2009), 129–38; Cronyn, The Elements of Archaeological Conservation; Catherine Sease, A Conservation Manual for the Field Archaeologists (Archaeological Research Tools Volume 4), 3rd edn (Los Angeles: University of California, 1994); Bradley A. Rodgers, The Archaeologist’s Manual for Conservation: A Guide to Non-Toxic, Minimal Intervention Artifact Stabilization (Dordrecht: Kluwner Academic Publishers, 2004).

4 See, for example, Cronyn, The Elements of Archaeological Conservation; Omid Oudbashi, ‘A Methodological Approach to Estimate Soil Corrosivity for Archaeological Copper Alloy Artefacts’, Heritage Science 6, no. 2 (2018), https://doi.org/10.1186/s40494-018-0167-4; Colin Pearson, Conservation of Marine Archaeological Objects (London: Butterworth Heinemann, 1987); Kirsty E. High and Kirsty E. H. Penkman, ‘A Review of Analytical Methods for Assessing Preservation in Waterlogged Archaeological Wood and their Application in Practice’, Heritage Science 8, no. 83 (2020), https://doi.org/10.1186/s40494-020-00422-y (both accessed 7 December 2023).

5 Chris Caple, Conservation Skills: Judgement, Method and Decision Making (Oxford: Routledge, 2004).

6 Cf. for example, Mohsen Javeri and Majid Montazer Zohouri, ‘Vigol and Harāskān Fire Temple: Archaeological Evidence About the Veneration of Fire in the Center of the Iranian Plateau During the Sasanian Period’, Iran: Journal of the British Institute of Persian Studies (2022), https://www.tandfonline.com/doi/abs/10.1080/05786967.2022.2037100 (accessed 7 December 2023).

7 Hasan Karimiyan and Mohsen Javeri, ‘Vigol and Harāskān, Two Cities; A Study Based on Archaeological Data in Transformation from Sassanid Era to the Islamic Period Relying Upon Archeological Data’, Journal of Archaeological Studies 1, no. 2 (2010): 63–83; Mohsen Javeri, ‘Space and Society of Iranian Cities in Transition from Sasanid to Islamic Period, Case Study of Vigol and Haraskan’ (unpublished PhD thesis, University of Tehran, 2007).

8 Javeri and Montazer Zohouri, ‘Vigol and Harāskān Fire Temple’; Karimiyan and Javeri, ‘Vigol and Harāskān, Two Cities’.

9 Mohsen Javeri, ‘The First Season Excavation at Vigol Site Report’ (unpublished, Archive of Archaeology Research Centre of Ministry of Cultural Heritage Organization of Iran, 2013).

10 Mohsen Javeri and Milad Baghsheikhi, ‘Comparative Comparison of the Architecture of the Sassanid Fire Temple and the Fire Base Discovered from Vigol and Harâskân with other Sassanid Religious Buildings’, Pazhohesh-ha-ye Bastanshenasi Iran 10, no. 27 (2021): 135–50 (in Persian); Javeri and Montazer Zohouri, ‘Vigol and Harāskān Fire Temple’.

11 For more details please see Javeri and Montazer Zohouri, ‘Vigol and Harāskān Fire Temple’.

12 Gakuto Takahashi, ‘Sample Preparation for X-ray Fluorescence Analysis III. Pressed and Loose Powder Method’, Rigaku Journal 31, no. 1 (2015): 26–30, https://www.911metallurgist.com/blog/wp-content/uploads/2015/09/XRF-Sample-Preparation-Guide.pdf (accessed 8 December 2023).

13 Cf. for example, Romain Bruder, Vincent Detalle, and Claude Coupry, ‘An Example of the Complementarity of Laser-Induced Breakdown Spectroscopy and Raman Microscopy for Wall Painting Pigments Analysis’, Journal of Raman Spectroscopy 38 (2007): 909–15; Lucia Burgio and Robin J. H. Clark, ‘Library of FT-Raman Spectra of Pigments, Minerals, Pigment Media and Varnishes, and Supplement to Existing Library of Raman Spectra of Pigments with Visible Excitation’, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 57, no. 7 (2001): 1491–521; Marc S. Walton and Karen Trentelman, ‘Romano-Egyptian Red Lead Pigment: A Subsidiary Commodity of Spanish Silver Mining and Refinement’, Archaeometry 51, no. 5 (2009): 845–60.

14 See, for example, Kamyar Abdi, Susan Pollock, and Reinhard Bernbeck, ‘Fars Archaeology Project 2003: Excavations at Toll-E Bashi’, Iran: Journal of the British Institute of Persian Studies 41 (2003): 339–44; W. David Kingery, Pamela B. Vandiver, and Martha Prickett, ‘The Beginnings of Pyrotechnology, Part II: Production and Use of Lime and Gypsum Plaster in the Pre-Pottery Neolithic Near East’, Journal of Field Archaeology 15, no. 2 (1988): 219–44; Abbas Motarjem and Mahnaz Sha, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, rifi, ‘Cultural Development of Chalcolithic Era in the East of Central Zagros based on Archaeological Excavations at Tepe Gheshlagh’, Iranian Journal of Archaeological Studies 4, no. 1 (2014): 49–65.

15 See Atefeh Shekofteh and Omid Oudbashi, ‘Chemical and Microscopic Investigation of Ancient Mortar and Plaster from the Middle Elamite Period Tepti Ahar’s Vaulted Tomb, Southwestern Iran’, International Journal of Architectural Heritage: Conservation, Analysis, and Restoration 14 (2020): 1269–83.

16 Cf. Parviz Holakooeia et al., ‘Colourants on the Wall Paintings of a Mediaeval Fortress at the Mount Sofeh in Isfahan, Central Iran’, Journal of Archaeological Science: Reports 29 (2020): 102065.

17 See Leila Khosravi, ‘New Archaeological Excavations of the Jahangir and Gowriyeh Manor Houses in the West of the Sassanid Empire’, Iran: Journal of the British Institute of Persian Studies (2021), https://doi.org/10.1080/05786967.2021.2006577; Jens Kröger, ‘Stucco Decoration in Iranian Architecture’, in Encyclopaedia Iranica Online (2005), https://iranicaonline.org/articles/stucco-decoration-in-iranian-architecture; Meysam Labbaf-Khaniki, ‘Excavations at Bazeh-Hur in North-Eastern Iran: A Preliminary Report’, Iran: Journal of the British Institute of Persian Studies 55, no. 2 (2017): 253–70; Yousef Moradi and Edward J. Keall, ‘The Sasanian Fire Temple of Gach Dawar in Western Iran: New Evidence’, Iran: Journal of the British Institute of Persian Studies 58, no. 1 (2020): 27–40, https://www.tandfonline.com/doi/full/10.1080/05786967.2019.1566761 (all accessed 8 December 2023).

18 Elisabetta Gliozzo and Corina Ionescu, ‘Pigments-Lead-based Whites, Reds, Yellows and Oranges and their Alteration Phases’, Archaeological and Anthropological Sciences 14, no. 17 (2022); Elizabeth West FitzHugh, ‘Red Lead and Minium’, in Artists’ Pigments’ Volume 1: A Handbook of their History and Characteristics, ed. Robert L. Feller (London: National Gallery of Art Washington/Archetype, 1986), 109–39.

19 Parviz Holakooei et al., ‘Micro-Raman Spectroscopy in the Identification of Wulfenite and Vanadinite in a Sasanian Painted Stucco Fragment of the Ghaleh Guri in Ramavand, Western Iran’, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 169 (2016): 169–74.

20 Parviz Holakooei and Amir-Hossein Karimy, ‘Early Islamic Pigments used at the Masjid-i Jame of Fahraj, Iran: A Possible Use of Black Plattnerite’, Journal of Archaeological Science 54 (2015): 217–27.

21 Parviz Holakooei et al., ‘Early Islamic Pigments at Nishapur, North-Eastern Iran: Studies on the Painted Fragments Preserved at The Metropolitan Museum of Art’, Archaeological and Anthropological Sciences 10, no. 1 (2018): 175–95.

22 Amir-Hossein Karimy and Parviz Holakooei, ‘Analytical Studies Leading to the Identification of the Pigments used in the Pīr-i Hamza Sabzpūsh Tomb in Abarqū, Iran: A Reappraisal’, Periodico di Mineralogia 84, no. 3A, Special Issue (2015): 389–405.

23 See, for example, Petr I. Kostrov and E. G. Sheinina, ‘Restoration of Monumental Painting on Loess Plaster Using Synthetic Resins’, Studies in Conservation 6, no. 2/3 (1961): 90–106; Norman Davey, ‘The Conservation of Romano-British Painted Plaster’, Britannia 3 (1972): 251–68; Stefano Pulga, ‘A Note on the Use of Silicone Rubber Facings in the Reassembly of Archaeological Painted Plasters’, Studies in Conservation 42 (1997): 38–42; Pamela Hatchfield et al., ‘Working Together: Community, Conservation, and Preservation Strategies for Royal Painted Tombs at El-Kurru, Sudan’, Studies in Conservation 65 (2020): 132–8; Shigemasa Udagawa, ‘The Protection and Utilization of Wall Paintings of Ancient Tumuli in Japan’, in Conservation and Painting Techniques of Wall Paintings on the Ancient Silk Road, ed. Shigeo Aoki et al. (Singapore: Springer, 2021), 305–23.

24 Cf. for example, Teresa López-Martinez, Francisco José Collado-Montero, and Ana Garcia-Bueno, ‘Ensayos de consolidación en pintura mural arqueológica: comparación de tratamientos en función de la técnica de ejecución’, Conservar Património 39 (2022): 33–44, https://doi.org/10.14568/cp2020040 (accessed 9 December 2023); Carl A. Grissom et al., ‘Evaluation Over Time of an Ethyl Silicate Consolidant Applied to Ancient Lime Plaster’, Studies in Conservation 44, no. 2 (1999): 113–20; Marta Caroselli, Silvestro A. Ruffolo, and Francesca Piqué, ‘Mortars and Plasters—How to Manage Mortars and Plasters Conservation’, Archaeological and Anthropological Sciences 13 (2021), art. no. 188, https://link.springer.com/article/10.1007/s12520-021-01409-x (accessed 9 December 2023).

25 See, for example, Sébastien Aze et al., ‘Red Lead Darkening in Wall Paintings: Natural Ageing of Experimental Wall Paintings Versus Artificial Ageing Tests’, European Journal of Mineralogy 19, no. 6 (2007): 883–90; David Saunders, Marika Spring, and Catherine Higgitt, ‘Colour Change in Red Lead-Containing Paint Films’, in ICOM Committee for Conservation 13th Triennial Meeting, Rio de Janeiro 20–27 September 2002: Preprints (London: James & James Ltd, 2002), 455–63.

26 Cf. for example, Fadwa Jroundi et al., ‘Consolidation of Archaeological Gypsum Plaster by Bacterial Biomineralization of Calcium Carbonate’, Acta Biomaterialia 10, no. 9 (2014): 3844–54; Evan Kopelson, ‘Analysis and Consolidation of Architectural Plasters from Çatalhöyük, Turkey’ (unpublished MSc thesis, University of Pennsylvania, 1996; D.S. Ramamurthi et al., ‘Effectiveness of Using Organic and Inorganic Consolidants on the Properties of Friable-Porous Gypsum Mortar’, Materials Today: Proceedings 62, no. 8 (2022): 5508–13; Abdullah M.A. Kamel, ‘Dehydration of Gypsum Component of Plasters and Stuccos in some Egyptian Archaeological Buildings and Evaluation of K₂SO₄ Activator as a Consolidant’, Scientific Culture 5 (2019): 49–59; Takayasu Kijima, ‘Conservation of Detached Wall Paintings from the Bamiyan, Foladi and Mes Aynak Sites’, in Aoki et al., Conservation and Painting Techniques of Wall Paintings on the Ancient Silk Road, 197–221; Lorenzo Lazzarini and Paul M. Schwartzbaum, ‘Technical Examination and Restoration of the Paintings of the Dome of the Al Aqsa Mosque, Jerusalem’, Studies in Conservation 30, no. 3 (1985): 129–35; Armand Vinçotte et al., ‘Effect of Solvent on PARALOID® B72 and B44 Acrylic Resins Used as Adhesives in Conservation’, Heritage Science 7 (2019), article 42; Grissom et al., ‘Evaluation Over Time of an Ethyl Silicate Consolidant’.

27 Sasha Chapman and David Mason, ‘Literature Review: The Use of Paraloid B-72 as a Surface Consolidant for Stained Glass’, Journal of the American Institute for Conservation 42, no. 2 (2003): 381–92; Stephen Koob, ‘Paraloid B-72®: 25 Years of Use as a Consolidant and Adhesive for Ceramics and Glass’, in Holding it All Together, ed. Janet Ambers et al. (London: British Museum/Archetype, 2009), 113–9.

28 Stephen Koob, ‘The Use of Paraloid B-72 as an Adhesive: Its Application for Archaeological Ceramics and Other Materials’, Studies in Conservation 31, no. 1 (1986): 7–14; Koob, ‘Paraloid B-72®’.

29 Sophia Sotiropoulou et al., ‘Microanalytical Investigation of Degradation Issues in Byzantine Wall Paintings’, Applied Physics A 92 (2008): 143–50; Eva Kotulanová et al., ‘Degradation of Lead-based Pigments by Salt Solutions’, Journal of Cultural Heritage 10, no. 3 (2009): 367–78; Alessia Coccato, Luc Moens, and Peter Vandenabeele, ‘On the Stability of Mediaeval Inorganic Pigments: A Literature Review of the Effect of Climate, Material Selection, Biological Activity, Analysis and Conservation Treatments’, Heritage Science 5 (2017), article 12; David Hradil et al., ‘Crocoite PbCrO₄ and Mimetite Pb₅(AsO₄)₃Cl: Rare Minerals in Highly Degraded Mediaeval Murals in Northern Bohemia’, Journal of Cultural Heritage 10 (2009): 367–78.

30 Shekofteh and Oudbashi, ‘Chemical and Microscopic Investigation of Ancient Mortar and Plaster’.

31 Margo Delidow, Jessica Pace, and Eric Meier, ‘Conservation of Christo/Paik Wrapped Tv (1967): Documentation and Treatment of a Collaborative Artwork’, Journal of the American Institute for Conservation 55, no. 4 (2016): 228–37; Ruth Chércoles Asensio et al., ‘Analytical Characterization of Polymers Used in Conservation and Restoration by ATR-FTIR Spectroscopy’, Analytical and Bioanalytical Chemistry 395 (2009): 2081–96; Dario Camuffo, Giovanni Sturaro, and Antonio Valentino, ‘Showcases: A Really Effective Means for Protecting Artworks?’, Thermochimica Acta 365 (2000): 65–77; Jerry Shiner, ‘Trends in Microclimate Control of Museum Display Cases’, in Museum Microclimates, ed. Tim Padfield and Karen Borchersen (Copenhagen: National Museum of Denmark, 2007), 267–75.

32 Kotulanová et al., ‘Degradation of Lead-based Pigments by Salt Solutions’; Ilaria Costantini et al., ‘Darkening of Lead- and Iron-based Pigments on Late Gothic Italian Wall Paintings: Energy Dispersive X-ray Fluorescence, μ-Raman, and Powder X-ray Diffraction Analyses for Diagnosis: Presence of β-PbO₂ (plattnerite) and α-PbO₂ (scrutinyite)’, Journal of Raman Spectroscopy 51, no. 4 (2020): 680–92.

Additional information

Notes on contributors

Omid Oudbashi

Omid Oudbashi is currently a senior lecturer at the Department of Conservation in the University of Gothenburg, Sweden. He worked as an associate professor at the Art University of Isfahan, Iran (2013–2023) and served as a senior Andrew W. Mellon Conservation Fellow in the Department of Scientific Research at the Metropolitan Museum of Art, USA (2022–2023). His main research interests are the deterioration of archaeological objects (especially the corrosion of ancient metals in terrestrial, marine and outdoor environments), preventive and archaeological conservation, archaeometallurgy and ancient metalworking, metallography of ancient and historic metals, and ancient techniques and methods of production and decoration in other inorganic materials.

Mohsen Javeri

Mohsen Javeri is an associate professor of Islamic archaeology and has served as the Dean of the Faculty of Architecture and Art at the University of Kashan, Iran since 2019. He was a faculty member of the Iranian Cultural Heritage Organization Research Center (2002–2010), deputy of research for the Cultural Heritage Organization of Isfahan Province (1997–2001) and director of the Cultural Heritage Organization of Kashan (2016–2019). He has published extensively in both national and international journals and his research interests include Islamic art and archaeology, the Sassanid-to-Islam transition period, and the excavation of Sassanian and Islamic sites. He has actively worked as the head of many excavation projects in several ancient sites in Iran and other counties such as at Qlahat in Oman.

Atefeh Shekofteh

Atefeh Shekofteh is currently the Senior Andrew W. Mellon Conservation Fellow in the Department of Scientific Research at the Metropolitan Museum of Art (USA) working on the analytical characterisation of Iranian gypsum artworks. She has conducted extensive research on the identification and characterisation of inorganic historical artifacts including pigments as well as stone, mortar and stucco decorations. Additionally, she has performed archaeometric investigations on several outstanding World Heritage Sites (WHS) in Iran including Pasargadae (2015–2016), the Anāhitā Temple of Kangavar (2018–2020) and Tāq-e Bostān in Kermanshah (2019–2021). She is currently involved in two research projects, ‘Identification of Polychromy Surface of the Relief Fragments from the Persepolis World Heritage Site in the Museum Collections of the USA’ and ‘Pigments from Persepolis and Pasargadae at the Metropolitan Museum of Art in New York City: Scientific Investigations’.

Sepehr Bahadori

Sepehr Bahadori is currently a PhD student in conservation of cultural and historical properties at the Art University of Isfahan, Iran. His research interests include archaeological and archaeometallurgical remains (including prehistoric metals, ores and slags) and multi-analytical methods involving chemical analysis and metallography.

Majid Montazer Zohouri

Majid Montazerzohouri is an assistant professor of Islamic archaeology at the University of Tehran, Iran. His research interests include archaeology of religions and rituals as well as the analysis of the Zoroastrian religion according to the material cultures. He has served as the head of the archaeology mission in four excavations and participated in 17 excavations as a mission member in Iran.