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.
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”.
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.
Lit.: E. Brepohl, Theory and Practice of Goldsmithing, Brunswick 2001.
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.
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.
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.
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.
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?
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)
The continental tradition with the use of garnets in jewellery from the early Middle Ages spread north up to Norway during the 6th and 7th centuries, albeit used in a much lesser degree. Garnets are, however, frequently used in the so-called disc-on-bow brooches. These are one of the most spectacular jewellery types we know of from this period in Scandinavia. They are usually made of gilded copper alloy and the surface is covered with garnets set in cloisonné technique. The manufacturing of the brooches take place in the period between c. 550–800 AD, i.e. the period leading up to the Viking Age. However, many of the brooches have been found in Viking graves, and are thus quite old when buried. How is this phenomenon to be understood?
This is the abstract of the presentation held during the lecture series in summer/autumn 2016.
During the fifth to seventh centuries AD, an ostentatious style of feminine dress flourished in Europe featuring large and decorative brooches. Thanks to the simultaneous (and perhaps not coincidental) rise of the furnished burial rite, thousands of these objects survive in museum collections. The geographical scale of this style was unprecedented, covering most of modern day Europe, from Norway to lowland Britain and Iberia, across to the Ukraine and up into the Baltic. As such, its analysis has much to tell us about contacts between populations in Europe, and how they used styles of jewellery as a means of creating and negotiating a material and social network. Traditionally, this material has been analysed using typology with the aim of grouping the material to reveal information about migration or ethnicity and more recently other forms of identity. Therefore, both the subject of enquiry and the method used in its investigation have a stated aim to reduce complex relationships into delineated groupings populated by objects or by people. In this presentation a new Europe-wide database of this material will be introduced and used to illustrate the possibilities of an alternative means of investigation. Instead of typology, a formal network analysis will be used to switch the focus of attention to the complex relationships between objects, and the web of linkages that these relationships create when examined en masse.
This is the abstract of the presentation held during the lecture series in summer/autumn 2016.
Present-day Sweden has a large and varied garnet material from the Iron Age. Even if there are finds dating back to the Late Roman Period most objects derive from the 5th to 8th centuries. In Sweden this time period is called the Migration and Vendel Period, and it is characterised by its regional power structures, wealthy burials and far-reaching networks of contacts. Most of the garnets are part of jewellery such as brooches but also adorning high status weaponry etc. Continue reading Garnet Jewellery in Early Medieval Sweden→
The usage of garnets on the continent changed markedly during the final decades of the 6th century. Objects with garnet inlay, which until then had been available to large parts of the population even in remote and rural regions, suddenly became scarce. The two general explanations are that cloisonné had either become unpopular, or that the trade links for the supply of raw material from Sri Lanka and India had been severely disrupted. Continue reading Garnet Cloisonné on the Continent during the 7th and 8th Centuries→
This subproject is concerned with basic research that is to say with the question of origin and stylistic development of cloisonné between India and the Byzantine Empire. Following a careful chronological classification, significant insight will be gained through a combination of published finds and some of the objects from the collections of the RGZM originating in this vast geographic area. Continue reading The Development of Cloisonné between India and the Byzantine Empire→
In the first half of the 20th century, some cemeteries with large amounts of grave goods dating from the early Visigothic period (5th-6th centuries) were discovered and excavated in central Spain. This material included large numbers of clothing accessories decorated in the cloisonné technique. At that time, they seemed to “complete” a general perception of Visigothic-period “minor arts”, joining the cloisonné-decorated crowns discovered in the late 19th and early 20th century at Guarrazar and Torredonjimeno, dating from the 7th century. Continue reading Cloisonné during the Visigothic period in Spain→
The aim of the research project is to examine the Northern Rhineland as a model region for trade and distribution of imported goods by analysing origin, quality of cutting and garnets framing during the Merovingian period. Continue reading Garnet Cloisonné in the Rhinelands→