On fire for granulation! – Experimental session in Toulouse, 4-8 June 2019
Since May 2019 Mrs. Svenja Simon is writing her master thesis on “Granulation in the Central European Iron Age – Archaeological and Experimental Investigations” at the Saarland University.
This topic was developed in close cooperation between her supervisor Univ.-Prof. Dr. Sabine Hornung and our CELTIC GOLD project. Therefore, the work is supported and co-supervised by Barbara Armbruster, Martin Schönfelder and Sebastian Fürst.
In her work, Svenja Simon, a trained goldsmith, deals with the history of granulation technology during the Iron Age in the area of Hallstatt and Latène culture, respectively. One focus lies on the technical production issues. Supported by scientific investigations such as SEM and LA-ICPMS, various fixation techniques are being tested.
Granulation is a technique developed during the Early Iron Age in Western Europe, which consists in producing small gold granules, then fixed together and/or on the object they adorn (fig. 1). During the Iron Age, there are at least 2 different ways of practicing granulation:
- the first, often attributed to the Etruscans, consists in soldering the granules using copper salts (malachite) mixed with an organic glue;
- the second, rather used by the Celtic craftsmen, consists in fixing the granules by metallic solder
Pin from a funeral pyre in Lazenay (Bourges, Cher), dating of the Vth century BC. It consists of a gold rod at the end of which is welded a hollow ram head with stylized horns. Two lines of 9 and 13 granules surround respectively the back of the head and the muzzle (photo B. Armbruster).
In order to be able to study the different granulation techniques, practical experiments had to be carried out. For this reason, Barbara Armbruster invited Svenja Simon in June to her workshop in Toulouse, to conduct these studies with her.
During 4-8 June 2019, they applied different granulation techniques and yielded exciting results and documentation. They created specimens, which have been microscopically documented, sawed into two halves and were then examined with the SEM. One half has already been analysed with LA-ICP-MS in Mannheim, the other half will be in Orléans to use the results as a standard and to further improve the knowledge of the analytical properties of different granulation techniques.
The experimentations in Toulouse showed that the granulation topic is more complex than we imagined, and that further experiments would be useful in general.
Example of gold granulation using copper salt (malachite) mixed with an organic glue (photo: S. Simon).
To go further (no exhaustive list)…
Armbruster 2013: ARMBRUSTER B. R. – Les techniques de l’orfèvrerie orientalisante : un cas de transfert technologique au début de l’Âge du Fer, Mélanges de la Casa de Velázquez, 43-1, 2013, p. 65-83.
Binggeli 2018: BINGGELI M. – Arten Goldkügelchen aufzulöten – Versuche zur Reaktionslöttechnik, Anzeiger Experimentelle Archäologie Schweiz, p. 6-9.
Duval et al. 1989: DUVAL A. R., ELUERE Chr., HURTEL L., MENU M. – The use of Scanning Electron Microscopy in the study of gold granulation, In: MANIATIS Y. (ed.) – Archaeometry: proceedings of the 25th international symposium, Amsterdam & Oxford: Elsevier, p. 325-333.
Milcent et al. 2018: MILCENT P.-Y., ARMBRUSTER A., BLET-LEMARQUAND M., GRATUZE B. – Les bjoux en or du tumulus princier du Ve siècle av. J.-C. de Lazenay à Bourges (région Centre-Val-de-Loire), In: SCHWAB R., MILCENT P.-Y., ARMBRUSTER B., PERNICKA E. (eds) – Early Iron Age gold in Celtic Europe. Society, Technology and Archaeometry, Proceedings of the International Congress held in Toulouse, Verlag Marie Leidorf, Rahden, p. 255-269.
Nestler et al 1993: NESTLER G., FORMIGILI E. – Etruskische Granulation. Eine antike Goldschmiedekunst (Siena 1993).
Nicolini 1990: NICOLINI G. – Techniques des ors antiques. La bijouterie ibérique du VIIe au IVe siècle, Paris: Picard, 2 vol.
Parrini u. a. 1982: PARRINI P., FORMIGLI E., MELLO E. – Etruscan Granulation:
Analysis of Orientalizing Jewelry from Marsiliana d‘Albegna. Am. Journal Arch. 86, 1 (1982) 118-121.