Tag Archives: Object Studies

Conference Proceedings: Gemstones in the first Millennium

Researchers from different fields like archaeology, history, philology and natural sciences present their studies on ancient gemstones. Using precious minerals as an example, trade flows and craftsmanship, but also utilisation and perception are discussed in a cross-cultural and diachronic approach. The present volume aims at three main questions concerning gemstones in archaeological and historical contexts: »Mines and Trade«, »Gemstone Working« as well as »The Value and the Symbolic Meaning(s) of Gemstones«.


This volume contains the proceedings of the conference »Gemstones in the first Millennium AD« held in autumn 2015 in Mainz, Germany, within the scope of the BMBF-funded project »Weltweites Zellwerk – International Framework«.

You can preview the table of content and a preface here.

Introducing the International Framework project

Dieter Quast and Alexandra Hilgner from the Römisch-Germanisches Zentralmuseum (RGZM) in Mainz explain the initial questions of the project “Weltweites Zellwerk – International Framework” regarding the origin and development of garnet cloisonné jewellery in the early middle ages. Garnet gemstones from India arrived in a vast amount during the 6th century in the Merovingian kingdom in central Europe. In the 7th century, the cloisonné jewellery style was suddenly disappearing. Was it because of a change in fashion or did something happen to the former trade routes? The International Framework project, organised by the RGZM, the SAI Heidelberg and the LVR-LandesMuseum, Bonn with partners in Sweden, the UK and Hungary tries not only to find answers to these questions regarding the value and the meaning of the gemstone garnet, but also to understand the international trade and economic interactions in the “dark ages”.

Technical Experiments 1: Producing a piece of silver foil

As an alternative to high karat gold foils fire-gilt silver foils have been used to produce the patterned Early Medieval backing foils. For my experiments, I needed a silver foil of a material thickness of 0,025 to 0,03 mm. My starting material was a sheet the size of 10×10 cm and a thickness of 1 mm. It was composed of 93,5% silver, 6,2% copper and 0,3% zinc. The authentic way to reduce the metal thickness would have been to draw down the material by forging. but to save time I decided to thin the sheet by rolling using a hand-operated rolling mill. The metal is worked in a cold state. It is primarily stretched in length. Because the process creates stresses in the crystal structure, the workpiece has to be annealed after several passes though the rolls: You have to heat it to a red state and then cool it down. Rolling the silver sheet to a material thickness of 0,03 mm would mean that its length expands up to 4 m! So repeated cutting off of smaller pieces was necessary. I started to roll the sheet immediately, reducing the distance between the rollers step by step, and I could go on until a material thickness of 0,1 mm was reached. Then the gap between the rollers couldn’t be made any smaller. So I continued sandwiching the silver between two copper sheets. During the whole rolling process the workpiece had been periodically annealed. The thinner the sheet became the greater was the danger of melting. Finally, I held two silver sheets, sizes 2,7×6,6 cm and 2,7×5,2 cm, of a material thickness of 0,03 mm in my hands, with some small stress cracks along the edges and both a little bit warped, probably because of an irregular roller pressure.

Fig.1: surface area melted during the annealing process, image field: 10,5×15,5 mm (photo: RGZM/Stempel)
Fig. 2: stress cracks along the edge of the sheet, image field: 8×12,6 mm (photo: RGZM/Stempel)


Lit.: E. Brepohl, Theory and Practice of Goldsmithing, Brunswick 2001.

Manufacturing and uses of backing foils – some technical experiments

Hello, I am Christiane Stempel, goldsmith, conservator and responsible for the technological examination of Early Medieval garnet objects that have been brought to the Römisch-Germanisches Zentralmuseum in Mainz for scientific analyses within the project “Weltweites Zellwerk”.

During my work, I made some observations that raised questions regarding the manufacturing and the use of the patterned foils behind the garnets.

Fig. 1: Schematic figure of an Early Medieval garnet cloisonné (photo: RGZM/Ober)

Transparent stones were often underlaid with gold foils to reflect the light through the stone. This is particularly important when the stone is backed up with cement. In the Early Medieval period textured backing foils were used on a large scale. The three-dimensional pattern increased the reflective effect. I examined a great number of objects from different find-spots in Sweden, Anglo-Saxon England and the Rhineland and I found all the varieties of pattern commonly known from the literature such as standard waffle, boxed waffle (Varying in the number of enclosed squares [9 to 25]), ring-and-dot, lozenge, boxed lozenge and rectangle (stack bond). They only differ in fineness (number of lines/mm), depth of texture and contour sharpness.

Fig. 2 a-f: Foil pattern (RGZM/Stempel)


Unfortunately, the project nears its end and I would like to use the remaining time to carry out some technical experiments:

Producing the pattern

There are indications (see figures 3-7) that at least a number of foils weren’t manufactured with dies. It looks as if lines were traced immediately on to the foils to form the grid pattern.

Fig. 3: Buckle, Ailenberg, Württembergisches Landesmuseum Stuttgart A.V. III333 (photo: RGZM/Stempel)
Fig. 4: Disc brooch, Junkersdorf, Römisch-Germanisches Museum Köln 51,539 (photo: RGZM/Stempel)
Fig. 5: Disc brooch, Monsheim, Römisch-Germanisches Zentralmuseum Mainz O.15370 (photo: RGZM/Stempel)
Fig. 6: Disc brooch, Iversheim, LVR Landesmuseum Bonn 1960.667 (photo: RGZM/Stempel)
Fig. 7: Disc brooch, St.Severin, Römisch-Germanisches Museum Köln 50.286 (photo: RGZM/Stempel)

N. D. Meeks and R. Holmes described in their article “The Sutton Hoo Garnet Jewellery” an experiment with a scriber that they used to draw the lines directly onto the foils. But in their opinion, the result was not satisfying. (N. D. Meeks/R. Holmes, The Sutton Hoo garnet jewellery: an examination of some gold backing foils and a study of their possible manufacturing techniques. Anglo-Saxon Studies in Archaeology and History 4, 1985, 143-157.) I would like to pick up the idea again, but instead of a scriber I will do the work with a profiled hand-operated tool, comparable to a creaser. It is used until today in bookmaking and leather processing to imprint decorative lines onto a leather surface. In contrast to a pointed scriber the elongated working face of a creaser can be of any cross-section.

Fig. 8: Creaser (photo: RGZM/Steidl)


The theory that has to be verified in practice is as follows:  The grid pattern can be formed with a sliding forward motion of the tool, running it along a ruler with moderate pressure to form parallel lines, then rotating the workpiece by 90 degrees and repeating the action. For my experiments, I will use a small creaser-like tool that I have made by removing the cut of a square rifle file. As foil materials, I will use tin foil (0.03 mm) as well as sterling silver foils of different thicknesses (0,025 mm to 0,04 mm).

Using foil for stone securing

Not a small number of foils seem to have a further purpose: In many cases, the foils are trapped between the stone edges and the surrounding metal of the setting. Is it possible to hold a stone in place with the foil?

Fig. 9: Disc brooch, Hürth-Kalscheuren, LVR Landesmuseum Bonn XV (photo: RGZM/Stempel)

If times permits, I would like to produce a foil in the way outlined above using a fire-gilded silver foil. In the next few weeks, I will report about my experiments and I am curious about the results and your comments.


Featured image: Buckle, Endre socken, Statens Historiska Museet Stockholm 484:12, detail: garnet cloisonné with foils behind the garnets. (photo: RGZM/Stempel)

Gemstones in pre-Islamic Persia: Selection and meaning of material and shape of Sasanian seals

Lecture held by Nils Ritter, Berlin

One of the most common class of artefacts of pre-Islamic Persia are gemstones, which were used as seals as well as jewellery. So far, almost 10.000 seals from the Sasanian period are known, whereas few material is known from the preceding Parthian period, yet.
Centred in Persia, the Sasanian dynasty ruled from the Euphrates to the Indus, holding a position of supremacy for more than four centuries (from AD 224 to 652). Their gemstones respectively seals have had the highest geographical and social distribution of all known periods of pre-Islamic Persia.
The Sasanians chose colourful gemstones of different shapes, predominantly made of microcrystalline varieties of quartz. They stand out in the art of seal-cutting of the late ancient world not only for their quantity and distribution, but also in the character of themselves: this class of artefacts is significantly standardized in material, colour, shape, imagery, style and cutting techniques.
In the present paper, I will focus on the selection, background, and meaning of the materials, the colours and the shapes of Sasanian seals in order to present the traditional and innovative values of this class of material culture.

Lecture held during the conference “Gemstones in the first Millennium AD. Mines, Trade, Workshops and Symbolism.” October 22nd, 2015 at the Roemisch-Germanisches Zentralmuseum, Mainz (Germany).

The Color and Material of Greco-Roman Magical Gemstones

Lecture held by Christopher A. Faraone, Chicago

In the Roman Imperial period inscriptions and new iconography appear for the first time on gems manufactured in the Mediterranean basin that clearly indicate these gems are being used as magical amulets. In the past scholars have argued that such amulets are a completely new phenomenon and that they reflect the sudden onset of anxiety or superstition, in the latter case brought on by closer Greek contact with “oriental” societies.  I have just completed an entire book arguing against this approach and suggesting instead that the key changes were (i) people began to inscribe on the gems words that they previously spoke over them; and (ii) they introduced new images of powerful new Ptolemaic gods such as Harpocrates or Sarapis. There were, however, also some important technical changes in the gems themselves, because in the Roman period gem-cutters began to use cheaper opaque stones of various colors, such as chalcedony or jasper, and they began to favor flat surfaces that allowed them more easily to carve figures in intaglio and text. A change, for example, from a convex carnelian to a flat red jasper. Scholars have paid close attention to the correlation between images and text on these gems, but not always to their media and in my lecture today I would like to explore the reasons why certain colors and media become important as amulets in this period. One important feature of these stones is their uncanny properties. Certain stones, for example, made a strange sound when shaken, emit an odor when rubbed, attract iron or straw or otherwise seem to straddle the boundary between the organic and the inorganic – were singled out by the Greeks as powerful and were used as amulets. In my paper this afternoon I will focus on a handful of these stones and show how the Greeks – as they were wont to do — borrowed some of these stones from the Near East (especially Mesopotamia, by way of Persia) and in other cases invented their own traditions by turning organic amulets, for instance the eyes of green lizards, into green gemstones or the use of brownish gemstones inscribed with the image of a scorpion to ward off brown scorpions.

Lecture held during the conference “Gemstones in the first Millennium AD. Mines, Trade, Workshops and Symbolism.” October 22nd, 2015 at the Roemisch-Germanisches Zentralmuseum, Mainz (Germany).

Symbolism of precious stones in Byzantium

Lecture held by Antje Bosselmann-Ruickbie, Mainz

Surprisingly, magic played an important part throughout the history of the Byzantine Empire, although it was a Christian state. Wide-spread representatives of the material culture of magic are amulets made from different materials, but prevailingly preserved in metal and stone. Most examples date from the Early Byzantine period (4th-7th century), however, later examples as well as written sources prove that amulets must have existed until the end of the Byzantine Empire in the 15th century. A great number was made of precious stone such as sapphire, emerald, agate, sardonyx, carnelian, jasper, amethyst or haematite. Their protective character was usually defined by a representation, e.g. of a demon or a figure defeating a demon. Beyond that, the material itself played an important role. We learn from written sources that magical properties and healing powers were ascribed to gemstones. One example is the amethyst, which was supposed to protect the wearer from insobriety (amethystos, Gr., ‘not drunk’). Byzantine writers such as Epiphanius of Salamis (4th century) or Michael Psellos (11th century) provide an insight into the magical properties ascribed to the stones which can vary depending on the source.

Lecture held during the conference “Gemstones in the first Millennium AD. Mines, Trade, Workshops and Symbolism.” October 22nd, 2015 at the Roemisch-Germanisches Zentralmuseum, Mainz (Germany).

Before the emporia: Garnets and elite exchange networks in the North Sea Zone, AD 400-700

Lecture held by Helena Hamerow, Oxford

This lecture will consider the exchange networks by which garnets – both as a component of ornamental metalwork and as a ‘raw’ material – circulated around the North Sea Zone during the fifth to seventh centuries, with a particular emphasis on Anglo-Saxon England. Possible entry points for this material and the mechanisms behind its distribution will be considered, as will the appearance and significance of raw, unmounted garnets deposited in bags or pouches in early medieval burials. Aspects of workshop production will also be touched upon, particularly in relation to composite disc brooches. Finally, evidence for the decline in the availability of garnets around the North Sea Zone will be considered, above all in the form of ‘cannibalized’ and recycled garnets.

Lecture held during the conference “Gemstones in the first Millennium AD. Mines, Trade, Workshops and Symbolism.” October 21st, 2015 at the Roemisch-Germanisches Zentralmuseum, Mainz (Germany).

Foto: West Hanney Brooch (detail), Institute of Archaeology Oxford University: Ian R.Cartwright (2013).

Fatimid rock crystal carving techniques (10th -12th century AD)

Lecture held by Elise Morero, Oxford

The Fatimid caliphs of the 10th- to 12th-century C.E. are well known for their patronage of luxury arts, especially carved rock crystal vessels, although the manufacturing techniques employed in their production remain largely unknown. The processes of Fatimid rock crystal carving were investigated using a multidisciplinary method based largely on: the observation at various scales of the manufacturing traces on the surface of the objects; tribological analysis; the analysis of archaeological and ethnographic data; and also experimental reconstructions of ancient techniques.
These complementary methods enabled us to identify the techniques and tool-kit used by Fatimid craftsmen. The hardness of rock crystal (Mohs scale 7.0), together with its homogenous crystalline structure, makes the use of percussive tools inefficient. Instead, the crystal must be ground away using an abrasive powder and a lubricant. The mixture was carried to the surface of the crystal using different tools put in motion by a horizontal bow-lathe. It was determined that a particularly famous group of seven ewers was produced by a few specialised workshops, probably located at Fustat (Old Cairo), in about the year 1000 C.E. 11

Lecture held during the conference “Gemstones in the first Millennium AD. Mines, Trade, Workshops and Symbolism.” October 21st, 2015 at the Roemisch-Germanisches Zentralmuseum, Mainz (Germany).

Foto: Fatimid rock crystal ewer (Francis Mills ewer – Keir Collection, Dallas Museum of Art)

An early medieval garnet workshop in Gamla Uppsala, Sweden

Lecture held by John Ljungkvist, Uppsala


The project “Gamla Uppsala – the emergence of a mythical centre”, has since 2009 conducted systematic studies in Gamla Uppsala to increase the knowledge of the long term structural history of the site. In the period c. 550-700, the place is transforming remarkably into a monumental site. This transformation of an already densely settled site involves the famous mounds, houses on artificial plateaus and recently discovered post row monuments. Three areas were in 2011 investigated in the centre of the Early Medieval manor area. Beyond a major reinterpretations of the great 7th c. hall/-sal, the excavation also contributed in shedding new light on settlement continuity, crafts, large scale household economy and regulations of the site between c. 400-1600 AD. Of particular interest for this presentation is the Northern Plateau, placed in a 90 degree angle in relation the great hall. This partially artificial plateau, house, in between earlier and later phases, two 6th c., two large burnt down houses from the 7th to 8th c. The older building, of which only small remains have been examined, proved to be a multi-functional crafts building where the garnet production is the most prominent activity. The building most likely houses tens of thousands of garnet fragments from the jewellery production, which makes it the so far largest production site found so far in Scandinavia.


Lecture held during the conference “Gemstones in the first Millennium AD. Mines, Trade, Workshops and Symbolism.” October 21st, 2015 at the Roemisch-Germanisches Zentralmuseum, Mainz (Germany).

Further reading on the web:

Blog by John Ljungkvist

Garnet jewellery in early medieval sweden (presentation)

Resources according to the archaeological research at Gamla Uppsala in Swedish:


Arkeologerna blog posts

Societas Archaeologica Upsaliensis

Upplandsmuseet Uppsala