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Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

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The use of non-destructive and non-invasive analytical methods is widespread in the archaeometric study of metal objects, particularly in the case of precious metal artefacts, from which sampling is not, or in a limited way, allowed due to their high value. In this study, we highlight the main advantages and limitations of non-destructive analytical methods used on three polychrome animal-style silver buckles from the mid-to-late-5th-century Carpathian Basin. Optical microscopic observations, handheld XRF, SEM-EDX and μ-XRD analyses were performed to determine the chemical composition of the metals and their decoration (gilding, garnet and niello inlays), as well as the microtexture and mineralogical composition of the niello, in order to gain a better understanding of the materials used and reconstruct the manufacturing techniques in detail. The buckles were manufactured from relatively high-quality silver derived from the re-use of gilded silver scrap metal and intentionally alloyed with brass or leaded brass. The presence of mercury indicated the use of fire gilding. The niello inlays are composed of mixed silver-copper sulphides, even reaching the composition of pure copper sulphide; this is for the first time, when copper sulphide niello is observed on a silver object. The almandine garnets most probably originate from Southern India and Sri Lanka.
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45
XII/1/2021
INTERDISCIPLINARIA ARCHAEOLOGICA
NATURAL SCIENCES IN ARCHAEOLOGY
homepage: http://www.iansa.eu
Possibilities and Limitations of Non-Invasive Analytical Methods in the
Examination of Garnet- and Niello-Inlaid Precious Metal Objects –
Case Study of Three Polychrome Animal-Style Silver Buckles
from the 5th-Century Carpathian Basin
Viktória Mozgai1*, Eszter Horváth2, Bernadett Bajnóczi1
1Institute for Geological and Geochemical Research, Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network (ELKH),
Budaörsi út 45, 1112 Budapest, Hungary
2Department of Archaeometry and Archaeological Methodology, Institute of Archaeological Sciences, Eötvös Loránd University, Múzeum körút 4/B,
1088 Budapest, Hungary
1. Introduction
The use of non-destructive and non-invasive analytical
methods is widespread in the archaeometric study of metal
objects, particularly in the case of precious metal artefacts,
from which sampling is not allowed (or only in a very limited
way) due to their high value. However, beside the advantage
of their non-destructive nature, each analytical method has
its own limitations as well, which have to be taken into
consideration during data evaluation and interpretation (e.g.,
precision, accuracy, surface morphology, surface alterations,
and object size). The advantages and limitations of non-
destructive analytical methods are presented in this paper
in connection with the detailed archaeometric study of three
cast, silver, rhomboid belt buckles from the second half of
the 5th century AD (Figure 1).
This study aims to determine the elemental composition
of the metal alloy and characterise the decoration
techniques (gilding, niello and garnet inlays). The

opportunities and limitations to the investigation. The
  
reconstruction of the organisational background of the
production; i.e., in revealing the sort of preceding use and
application phases, which attests the economic value of
the given raw materials in the period, and on the other

*Corresponding author. E-mail: mozgai.viktoria@csfk.org
ARTICLE INFO
Article history:
Received: 9th
Accepted: 12th

Key words:
polychrome precious metal object
Carpathian Basin
garnet provenance
gilding
hXRF
SEM-EDX
µ-XRD
ABSTRACT
The use of non-destructive and non-invasive analytical methods is widespread in the archaeometric
study of metal objects, particularly in the case of precious metal artefacts, from which sampling is not,
or in a limited way, allowed due to their high value. In this study, we highlight the main advantages and
limitations of non-destructive analytical methods used on three polychrome animal-style silver buckles
from the mid-to-late-5th-century Carpathian Basin. Optical microscopic observations, handheld XRF,
SEM-EDX and µ-XRD analyses were performed to determine the chemical composition of the metals
and their decoration (gilding, garnet and niello inlays), as well as the microtexture and mineralogical
composition of the niello, in order to gain a better understanding of the materials used and reconstruct
the manufacturing techniques in detail. The buckles were manufactured from relatively high-quality
silver derived from the re-use of gilded silver scrap metal and intentionally alloyed with brass or leaded
      

time, when copper sulphide niello is observed on a silver object. The almandine garnets most probably
originate from Southern India and Sri Lanka.
IANSA 2021 ● XII/1 ● 45–67
Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

hand, in assessing the presence of any alloying practice and
standardisation.
From the middle of the 5th century AD, silver became
a more important raw material than gold. The combination
of these two precious metals provided a new opportunity to
        
material or gold plates on silver objects, typical for the
       
(Horváth et al.et al.

      
the key to identify the process of its making and fusing.


Since the discussed buckles have close relations with late
Roman military equipment in several aspects (Böhme,

microtexture of niello inlays may provide relevant new
results. Analytical data are expected to prove or disprove the
continuity of the late Roman niello recipes and technology.
In contrast with the silver alloy and niello inlay,
the garnet inlays represent a primary raw material of
natural origin. During data evaluation, no chemical
     
be considered. Therefore, in the case of garnet, we could
target the localisation of potential geological sources or
   e.g., alluvial or mined
garnet). The proportions of major, minor and trace elements,
as well as the combination of special inclusions, have proved
 
Figure 1. The analysed polychrome animal-style rhomboid silver buckles. A: the buckle from Zsibót-Domolospuszta (buckle ZsD) (Janus Pannonius
            
provenance (buckle UP) (Hungarian National Museum, Budapest). The tongues associated with the buckle with unknown provenance (buckle UP).
D: tongue decorated with a bird’s head; E: tongue decorated with a bird and boar head (photos: E. Horváth).
0 10 cm
0 10 cm
0 10 cm
0 10 cm
IANSA 2021 ● XII/1 ● 45–67
Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

provenances. Corresponding archaeometric investigations
are being performed worldwide, used as a reference for our
new measurements (e.g.et al.
Gilg et al.et al.
et al.et al.
studies are performed in order to extend our knowledge
about the used trade links and the organisational background
of supply in the Early Middle Ages, when garnet inlaid
jewellery had an unprecedented spread.
2. Archaeological background and analysed artefacts
The belt buckles involved in the analysis represent one of
the most emblematic metal artefacts in the middle-second
half of the 5th century AD. Their main characteristics are
the silver metal, the rhomboid shape and the decoration in
polychrome animal style (Table 1; Figure 1). All of the three
examples discussed here are from the Middle Danube Region
       
Table 1. The analysed polychrome animal-style rhomboid silver buckles, their decoration techniques and the number of garnet inlays. L: length; H: height;
W: width.
Provenance site Abbreviated
name
Sizes Decoration techniques Garnet inlays
(original/missing)
Chip-carving Gilding Niello inlays Garnet inlays Loop Tongue Plate
Zsibót-Domolospuszta buckle ZsD
L: 15.3 cm


X X X X  
unknown
(Hungary) buckle UP
L: 22.1 cm


X X X X   
Bácsordas
(Karavukovo) 

W: 5.9 cm

X X X X  
Figure 2. Distribution of cast silver rhomboid belt buckles with polychrome ornamentation in the Middle Danube Region (after Horváth et al.
      
previously analysed (Horváth et al.             
an unknown Hungarian site.
0 10 cm
IANSA 2021 ● XII/1 ● 45–67
Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

(hereafter called: buckle ZsD; Baranya county, Hungary;
Figure 1A), the second one from Bácsordas (hereafter called:
     
Serbia; Figure 1B), and the third one from an unknown
Hungarian site (hereafter called: buckle UP; Figure 1C). Two


th century (Hampel,

These examples have around a dozen close analogies
spread around by the Great Migrations (4th–5th centuries
AD) from the Middle Danube Region to Northern Italy and
  
Only one of them, the buckle from Gáva (Szabolcs-Szatmár-
Bereg county, Hungary; Hampel 1911; Figure 2), had been
investigated by archaeometric analysis (Horváth et al.
Using the available data, we are focusing on this buckle as a
highlighted item of comparison in our study.
Besides their common material and technological traits,
       
ornamentation and style. The items discussed here represent

subgroup (buckles from Bácsordas and Zsibót) are decorated

down, and a round or drop-shaped garnet inlay in the middle
of the front-plate (Figure 1A–B). In the second subgroup (the
buckle of unknown provenance), the front-plate is framed
with a bird-head frieze. In the middle of the plate, there
are garnet inlays in rhomboid shape cloisonné (cellwork)
(Figure 1C). The third subgroup (the buckle from Gáva)
represents the so-called mask buckles (Maskenschallen) that
are characterised by a mask motif and a plate closing in the
          
(Figure 2).
These buckles were unique prestige objects of the mid-
to-late 5th-century female aristocracy. They were produced
and worn in a short period spanning one or two generations.

         
between the Hunnic Period (early-to-mid 5th century AD)
  
th century AD) in which mass
products were more typical. In the Hunnic Period, hammered
and soldered gold objects are abundant, whereas the
      

of the goldsmithing traditions and their organisational
background are expected to be manifested on these objects.
The studied buckles were constructed of three, separately
cast elements and a hammered piece. The former, i.e., the
rhomboid-shaped, highly decorated front-plate (body), the
         
joined to each other by hinge and hook. The fourth element,
an undecorated thin back-plate, which might have served to
clamp the belt, was fastened by rivets. Among the analysed
objects, the back-plate was preserved only on buckle ZsD
(Figure 1A). Broken remains of fastening rivets suggest that
originally, similar back-plates might have been attached to
the rhomboid body of the other buckles too (Figure 1B–C).
The cast parts were manufactured by lost-wax casting,

probably prepared by applying two-part auxiliary moulds,
which represented the negative version of the main design:
the base form and most of the chip-carving ornamentation.
The wax model itself represented the positive, i.e. identical

such as cavities for inlays, holes for fastening rivets and
even some of the punch marks were created at this stage by
modelling the wax. The casting resulted in an intermediary
design of the artefact; the following post-casting process
included the decorative techniques and at the end, the
construction of the separately made elements.
Figure 3.    
techniques used on the buckles resulting
      
  
gilding (yellow arrows), niello inlaying
(blue arrows), garnet inlaying (red arrows)
(photo: E. Horváth).
IANSA 2021 ● XII/1 ● 45–67
Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin
49
The characteristic polychrome decoration appears in the

          


of periods and geographic areas, the combination of these
two is a speciality, typical only for the mid-to-late 5th-century

Buckles B and ZsD were preserved in their original (in
some places incomplete) state during restoration, while the
broken hinge of buckle UP was reinforced with a modern
supplement (Figure 1C).
Two loose tongues were supposed as potential accessories
that belonged to buckle UP; one of these has an ornament
in the shape of a bird’s head, while the other is decorated
with a bird and boar head (Figure 1D–E). As a detailed
archaeometric analysis had not been conducted before, it
was unclear which of these tongues could originally belong
to buckle UP. The tongue with a bird’s head has the richest
niello decoration. This artefact has a unique ornamentation,
as niello mass was applied irregularly on the inner surface
of the tongue in addition to the pre-made (punched, carved)
depressions (Figure 1C).
3. Methodology
In accordance with the artefact protection regulations, only
non-destructive and non-invasive methods were allowed to
be used. In addition, the size of the objects also limited the
range of available methods and analytical equipment that
could be used, requiring the use of either handheld equipment
    
Furthermore, the surface and accessibility of the measurement
points were not always optimal either. The polished surface

similar to that of polished sections, whereas in the case of
 
post-burial alteration (e.g., corrosion processes). Post-burial
alteration did not modify the mineralogy of the inlays (e.g.,
Table 2.et al.
Analytical method Application Pros Cons
hXRF*
– chemical composition
simultaneous, multi-element
method
full concentration range (Z=12–92)
– major, minor, trace elements
– fast
– cheap
– portable
– non-destructive
no sampling is needed (non-
invasive)
in most cases, no sample
preparation is needed
surface method (upper few tens
or hundreds of micrometres)
(inhomogeneities in the objects
due to e.g., phase segregation,
corrosion, surface treatments)

are needed)
– standardisation
SEM-EDX
chemical composition and
microtexture
– major and minor elements
– elemental mapping

(tool marks, wear traces, etc.)
– fast
– cheap
– small spot size (1 µm)
– non-destructive
no sampling or special sample
preparation are needed for
conductive materials (non-invasive)
surface method (upper few
micrometres) (inhomogeneities in
the object and surface treatments)

are needed)
sample chamber limits the size of
the objects to be analysed
in case of non-conductive materials
(e.g. garnets, glass inlays) special
sample preparation is needed
– standardisation
µ-XRD**
mineralogical composition (phase

– fast
– non-destructive
no sampling or special sample
preparation is needed (non-
invasive)


sample may cover certain areas of
the detector, some higher dhkl values
cannot be detected)

single crystal, nor represent ideal
powder, therefore the measured
peak intensities are increased

crystallographic directions due to
preferred orientation
during data evaluation only peak
positions can be used
the smaller collimator is used, the
longer measurement time is needed
– sample size is limited
IANSA 2021 ● XII/1 ● 45–67
Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

garnet or niello), only corrosion products of the metal can
deposit on their surfaces. However, during the corrosion of
precious metal objects (e.g., silver alloys), the base metals
(copper, lead) are leached out and silver and gold is enriched
et al.

microscopy to characterise the manufacturing techniques,
tool marks and garnet inclusions. The chemical composition
of the metal alloy and the gilding was analysed by using
     
cleaning was performed prior to the measurements, and we

   
and niello inlays. The high value of the objects meant that it
was not appropriate to abrade the surface in order to expose
the underlying metal over an area of about 3 mm in diameter
2); large enough to match the XRF beam, especially
on the highly decorated, clearly visible sides; therefore, the
reverse, undecorated sides were measured. Each part of the
buckles was analysed at 1–2 points. The hXRF is not an ideal
method for analysing niello and garnet inlays. The niello
inlays are too small and could not be analysed separately
from the metal alloy. In addition, due to limitations of the
built-in calibrations of hXRF, the exact composition of the
garnet inlays could not be determined either. Therefore,
SEM-EDX was used to determine the chemical composition
and microtexture of the niello inlays as well as the chemical
composition of the garnet inlays.
As garnets are non-conductive materials, a special sample
 et al.
       
was wrapped by using aluminium foil and carbon tapes.
The foil was pierced above the garnets, leaving a small
“window” to be carbon coated. After the coating process,
the object is unwrapped making it possible to analyse the
garnet and niello inlays and the metal alloy simultaneously.
As surface treatments (e.g.
the imaging, the analysed area was thoroughly cleaned with
      
more problematic in the case of SEM-EDX than in the case
of hXRF; therefore, we tried to analyse surfaces that are as

polished garnet surfaces immediately after measurements by
using ethanol and gentle manual rubbing.
The mineralogical composition of the niello inlays of the
buckles presumed on account of the SEM-EDX results was

3.1 Optical microscopy (OM)
       
microscopes and a Zeiss AxioScope A1 upright light
microscope equipped with a Zeiss AxioCam MRc5
microscope camera (5MP) were used.
3.2 Handheld X-ray uorescence spectrometry (hXRF)
      
      

Elements” built-in calibration, 3 mm measurement area,
     
calibration does not calculate the mercury content; therefore,
the presence of mercury can only be determined qualitatively
based on the hXRF spectra.
3.3 Scanning electron microscopy with energy-
dispersive X-ray spectrometry (SEM-EDX)

with Oxford Instruments INCA ISIS energy-dispersive X-ray
    

        
quantitative analysis, the following built-in factory standards
were used: MgO, Al2O3, SiO2, wollastonite, Ti, Cr, Mn, Fe,
FeS2, Cu, Ag, Au, and HgTe. Each garnet was analysed with at
least three (in the case of non-ideal surfaces more than three)
point (spots 1 µm in diameter) and one area measurements

       
“Excellent” results were used for interpretation. The average

in those cases where no better-quality measurements were
received. The “poor-quality” data were treated separately.
3.4 Micro-X-ray diractometry (µ-XRD)


third generation microfocus, sealed tube X-ray generator
and a curved imaging plate detector, was used. The
 radiation generated
         
         
analyses. A built-in CCD camera was used to select the
measurement areas. A laser scanning readout system reads
the imaging plate detector in about 1 min. RIGAKU 2D
Data Processing software 2DP was used to record the
        

      
software was used for data processing.
4. Results
4.1 Silver alloy composition
The buckles were manufactured from high-quality silver
       
Figure 4). Beside the typical minor and trace elements (gold,
lead, and bismuth), zinc was detected in each of the buckles.
       
plate) of buckle ZsD (Figure 1A) were manufactured from
       
         


IANSA 2021 ● XII/1 ● 45–67
Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin
51
Table 3.

Description Ag Cu Au Pb Bi Sn Zn Au/Ag Bi/Pb Hg
The buckle from Zsibót–Domolospuszta (buckle ZsD)
loop   2.1 1.2  < LOD   
tongue  5.9    < LOD   
back-plate 95.4 2.9    < LOD < LOD  
front-plate   1.5 1.5  < LOD   
gilding 19.9   < LOD < LOD < LOD  +
The buckle with unknown provenance (buckle UP)
loop  12.9    < LOD 1.4  
front-plate      < LOD   
tongue with bird-head   1.2   < LOD   
tongue with bird- and boar-head     < LOD < LOD  
gilding 13.9 1.3  < LOD < LOD < LOD  +
The buckle from Bácsordas (buckle B/K)
front-plate 91.1   1.2  < LOD 1.2  
loop    2.5  < LOD 1.1  
tongue  5.3    < LOD 1.2  
gilding 14.4 1.4  < LOD < LOD < LOD  +
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Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin
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
buckle
B/K (Figure 1B) were manufactured from a rather similar
       

the lowest gold content among the buckles. In contrast, there




       
buckle UP      


   

of the tongue with the bird’s head is similar to that of the
front-plate of the artefact, while the tongue decorated with


4.2 Niello inlays
The buckles were extensively decorated with niello inlays.
The design of the niello decoration usually shows coherency
           
ornamentation is mostly smooth and regular on the loop and
the tongue, while on the plate it is conceptually defective and
deteriorated in several places.
The elemental composition of the niello inlays is very
       
       

sulphide (Table 4; Figure 5). The surface of the niello inlays


of the niello shows inhomogeneities: lighter and darker
phases alternate with each other in the BSE images. In the
niello inlays of buckles ZsD and UP the irregular darker
phases a few tens of micrometres in size are Ag-Cu sulphides
or Cu-sulphides, while lighter phases are metallic silver-
copper alloy (irregular shaped, a few tens of micrometres
in size) or contamination with mercury and gold (narrow
strings along the grain boundaries, a few micrometres in

darker phases a few hundreds of micrometres in size are Ag-
Cu sulphides with higher copper content, while the irregular,
string-like lighter phases a few tens of micrometres in size

Figure 4. Composition of the three buckles based on the hXRF measurements. Black triangle: tongue with a bird’s head of the buckle UP, white triangle:
tongue with a bird and boar heads of the buckle UP. Elemental composition of silver objects from the 5th century AD is depicted for comparison (unpublished
data).
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Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin
53
Table 4.
Description wt% → Ag Cu S Au Hg at% → Ag Cu S Au Hg
The buckle from Zsibót-Domolospuszta (buckle ZsD)
front-plate niello 1 sp5 lighter      
niello 2 sp1 lighter   2.1    13.1   3.2
sp2 darker   15.1 21.2  29.9
niello 3 sp2 lighter    21.9   2.9 12.2
sp4 lighter   1.1 14.4    
sp5 lighter   1.9 9.9  15.4 5.9 
niello 4 sp2 lighter      5.4  11.3
sp3 lighter      12.4 5.9 
loop niello 4 sp1 lighter      
sp2 darker    2.5  34.5
sp3 lightest   23.9  14.2 
niello 5 sp2 darker 2.5   1.3  
sp3 lightest      19.5 
sp4 lighter   15.3   32.2
 sp1 darker 13.5  19.9   
 sp1 darker 12.9   1.2    
sp2 lighter 44.5  15.3   41.2 31.5 
niello 9 sp2 darker     34.3 
sp3 lighter     52.9 25.3  
 sp1 darker 21.9     
sp3 lightest  24.9 12.3 42.9  
sp4 lighter  45.9   45.4 32.9
niello 13 sp1 darker    2.1  
sp2 lighter     35.4   3.4
sp3 lighter  31.4  12.3 25.5 34.3  4.3
sp4 lightest   2.4  15.9  
niello 15 sp1 darkest   19.3 4.5  33.1
sp2 darker     52.3 31.3
sp3 lighter  31.1     23.1 4.2
tongue niello 1 sp3 lighter  21.5    
sp4 darker 59.9 21.5    
sp5 lighter   13.3 43.3  
niello 3 sp2 darker  19.3    25.9
sp3 lighter  1.4  2.4
sp4 darker   9.1   
sp5 lighter  3.3   5.4 2.9
niello 5 sp2 lighter  1.1   1.9 
sp3 darker   15.2   
sp4 lighter  2.1   3.5 
sp5 darker     23.2 
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Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin
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Description wt% → Ag Cu S Au Hg at% → Ag Cu S Au Hg
The buckle with unknown provenance (buckle UP)
front-plate niello 1 sp3 lighter  52.4    
sp4 darker      
niello 2 sp2 darker    21.3 45.5 33.2
sp3 lighter 44.5    39.5 
sp1 lighter     35.2 
sp2 darker 53.4 32.1    31.3
sp4 lighter     39.3 
sp5 darker      31.3
sp1 lighter  51.3    34.9
sp2 lightest   2.1      5.9 4.2
sp3 lighter 41.3 42.2  24.5 42.4 33.1
sp5 lighter   15.4   
 darker 33.5    45.3 35.9
The buckle from Bácsordas (buckle B/K)
plate niello 3 sp1 darker    15.3  34.2
sp3 lighter  12.1    14.1
sp1 lighter   13.2 32.1  
sp2 lightest 94.9 3.9 1.2   3.9
sp4 darker     39.4 32.9
niello 4 sp1 darker 39.1   23.4  
sp2 darker 35.2  14.5   
sp3 lighter    43.9 31.5 
sp3 lightest   95.4 
sp4 darker      33.2
sp5 lighter  49.9 11.4 23.9 52.3 
niello 5 sp1 lighter  9.2 3.1   
sp2 darker  43.4  24.3  
sp3 darkest      
niello 4 sp1 darker 39.3  14.3   
sp2 lighter      5.3
sp1 darker     33.5 
sp2 lighter      
 sp1 lighter  14.3   19.2 
sp3 darker      29.9
sp1 lighter  4.4    
sp2 darker 19.1     32.5
sp4 darker 29.3  12.1   
sp5 lighter 39.9   24.2  
Table 4.Continuation)
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Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin
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As these pieces are mounted, it proved impossible to analyse
the full range of mineral inclusions in the individual garnets.
This limited access is a general problem; loose, unmounted
        
       
their morphology. Most of these are accessory minerals
(e.g., rutile needles, ilmenite plates, isometric zircon, and
xenomorph quartz crystals) that are not indicators for the
source rocks. From this aspect, kyanite crystals and curved
needles of sillimanite, detected in a group of the slabs, are
of greater importance since they indicate medium- to high-
grade metamorphism at medium pressure (Figure 9A–B)
(Spear, 1995). One typical combination of inclusions occurs
extensively in the garnets of buckle ZsD: these are extremely

 
the large, clear apatite crystals in the garnets of the tongue
with the bird and boar heads, belonging to buckle UP.
From among the 55 garnet inlays preserved in the settings
of the buckles, 45 pieces were analysed by SEM-EDX.
Based on the chemistry, the garnets used for inlays are
from the pyralspite (pyrop-almandine-spessartine) series,
namely almandine with varying Ca, Mg and Fe contents
        
Mg concentrations, often referred to as intermediate
The results of the µ-XRD measurements proved the
presence of stromeyerite (AgCuS), digenite (Cu9S5)
and metallic silver in the niello inlays of the buckles

boar heads was studied only by using µ-XRD and revealed
that the niello inlay is composed not only of stromeyerite
and metallic silver, but also jalpaite (Ag3CuS4) and acanthite
(Ag2
4.3 Gilding
The buckles were extensively gilded. The gold content of the

on the hXRF measurements (Table 3), indicating a rather
thick gilding. The thickness of the gilding is estimated to be
around several tens of micrometres based on BSE images
         

4.4 Garnet inlays
Red garnet inlays played an important role in the decoration
of the buckles. Highlighting the eyes and mouth of the bird
         
precious metals and niello (Figure 3). The prevailing shape

rectangular, lunula- and drop-shaped pieces are also present.
Figure 5.   
      1.55CuS-Ag1.5CuS); Skinner et al.      CuS-
Ag1.25CuS), and Frueh (1955) and Tokuhara et al.Cu1.1S-AgCuS), respectively.
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Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

Figure 6. Backscattered electron images of the niello inlays and gilding of the buckles. A–B: niello inlays were put in previously carved recesses, the surface


pyrope-almandine crystals (Gilg et al.
   
on the buckles.
5. Discussion
5.1. Silver alloy composition
The buckles were manufactured from relatively high-quality
       
the general trend that during the 5th-century AD a gradual
debasement of silver alloys occurred towards the end of
the century (Figure 4) (Horváth et al.et al.,
th century AD is characterised
with high-quality silver alloys with low Au, Pb and Zn
and varying Bi content similar to late Roman silver alloys
  et al.

et al.
et al.et al.et al.,
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Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

Figure 7. Typical µ-XRD patterns of the niello from the buckles. A: tongue of buckle ZsD; B: loop of buckle ZsD; C: tongue with a bird’s head of buckle


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Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

Figure 8. Typical XRF spectra of the gilded areas of the buckles.
Figure 9.
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Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin
59
Figure 10. Ternary plots showing the composition of the garnets from the buckles based on the cation occupancy of the X site in the garnet structure
calculated from the SEM-EDX data (after Grew et al.
and boar heads of buckle UP.
  et al.      
alloys with high Cu, Pb, Zn and Sn content, reaching even the
1:1 Ag:Cu ratio (Figure 4), are more typical for the end of the
5th century AD (Horváth et al.et al.
Pure silver is too soft for making silver objects of use,
         
bend and wear easily. The most common alloying metal in
silver is copper, which improves the mechanical properties
of soft silver (e.g., increases strength and durability). During
silver extraction, the copper content could be reduced to even
      

The measured elements other than silver and copper are
naturally occurring, unintentionally or intentionally added
elements, deriving from the silver ore or from the copper

In antiquity, the main source of silver was silver-
       
silver ores were roasted, melted and cupelled during silver
     
from impurities (mainly from antimony, arsenic, tin, iron,
and zinc; less well from copper, gold and bismuth). The
volatile elements (antimony, arsenic, mercury, tin and zinc)
disappear from molten silver during cupellation (Pernicka,
et al.   
  
pure copper, but brass was added to the silver as an alloying

the melting point. The more copper is added to molten
silver; the more yellowish tint the alloy will have. This can
be overcome by adding zinc to the alloy, which will act as a
       
addition of zinc also prevents molten silver from oxidation and
bubbling, and enhances tarnish-proofness resulting in a much
  

ductility making tin-enriched silver alloys more ideal for sheet
    th-century
       
alloyed the silver with Zn (or Sn), beside copper.
If silver originates from silver-bearing lead ores (galena,
anglesite or cerussite), the lead content in the silver alloy
    
        
         
      
indicating that leaded copper or leaded brass was used for
alloying.
Bismuth is a good geochemical indicator that helps
identifying the provenance of silver objects, as its concentration
remains relatively constant during cupellation (Pernicka and
     et al. 
Based on experiments, bismuth is oxidised only in the very
last stages of cupellation and, therefore, bismuth in silver
objects is correlated with the degree of cupellation. However,
          
initial Bi content of the silver-bearing lead ores (L’Héritier
et al.
consistent, except the back-plate of buckle ZsD (Figure 4),
which is typical for the silver alloys from the middle and end
of the 5th century AD (Horváth et al.   et al.,

5th century AD and from late Roman times. The latter usually

et al.,
  et al. et al. 
Mozgai et al.et al.

IANSA 2021 ● XII/1 ● 45–67
Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

Table 5.           


Description No. SiO2Al2O3MgO CaO MnO FeO
The buckle from Zsibót-Domolospuszta (buckle ZsD)
front-plate grt 1 3      31.5±1.4
grt 2 1   3.3   31.4
grt 3 2    3.1 
grt 4 4     
grt 5 5      
 1 25.9  2.2  43.4
 3     
 4     41.1±1.5
 1  5.4 2.3  
grt 11 4      
grt 12 2  22.3  3.3  31.4
tongue grt 1 2 35.3  3.1 2.4  33.2
grt 2 1  21.3 4.4 1.4  32.9
The buckle with unknown provenance (buckle UP)
front-plate grt 1 1     
grt 2 4      
grt 3 1   5.3  2.1 
grt 4 1      29.9
grt 5 1   5.4 1.4  32.9
 4     
 1   1.3 1.2 34.9
 1     31.5
grt 9 3     
 2     
grt 11 1      
grt 12      
grt 13 1    32.1
grt 14 1    1.4 2.3 29.3
grt 15 1  21.1   3.3 
 4     
grt 19 4      
 2    31.4
grt 21 1  21.5  1.4 1.2 29.5
grt 22 3     
grt 23 3      
IANSA 2021 ● XII/1 ● 45–67
Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

Description No. SiO2Al2O3MgO CaO MnO FeO
tongue with bird- and boar-head grt 1 1    4.5  
tongue with bird-head grt 1 1 39.1 21.3  1.4  
The buckle from Bácsordas (buckle B/K)
front-plate grt 2 4      
grt 3 3      
grt 4 1  21.4 12.3 3.3  
grt 5 3      
 2 19.9 5.9 1.3  
 2   1.3 29.9
 1    1.5 
grt 9 2 41.1  11.3 2.1  23.2
 4     
Table 5.           

Continuation)
5th century AD may be the result of gradual recycling and


Gold is completely miscible with silver. During
metallurgical processes, the gold content of the silver
does not change radically (L’Héritier et al.   
       
      
     
      
are possible for higher gold concentrations, e.g., remnants
of former gilding, the re-use of scrap gilded silver, or the
use of gold-silver ores. In the case of buckles, as recycling
was proven by other elements as well, it is safe to say that
most probably re-used scrap gilded silver was utilised for
manufacturing.
The polychrome animal-style silver buckle from Gáva,
previously analysed by Horváth et al.  


        
    
      
from Gáva, indicating the use of leaded bronze or gunmetal
for alloying.
       
         
manufacture. The shortage of raw materials towards the end
of the 5th century AD resulted in the re-use and recycling
       
alloy compositions, even within one single object, indicate
that there was no conscious or standardised alloying practice
adopted by 5th-century AD goldsmiths.
The only undecorated back-plate that was analysed in the
        

of the buckle and shows similarities to late Roman silver
alloys (high silver content, relatively low gold, lead and
copper content, and no zinc) (Figure 4). It may have been
manufactured by melting Roman silver objects directly,
without further alloying.
5.2 Niello inlays
The bluish-black niello has been widely used to decorate
silver, gold and copper-based alloy objects. Chemically,
niello is composed of the sulphide of one or more metals,
fused or inlaid into a recess carved into the metal surface.
The composition of niello changed over the course of time
depending on what type of metal it decorated (Rosenberg,
      et al. 
    et al.   

Niello technique was much used in the early Middle
Ages, but there are still uncertainties concerning the niello
technique (exact composition, preparation and application)
used in this particular period. It has been widely accepted
that during the Roman period niello was generally composed
IANSA 2021 ● XII/1 ● 45–67
Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

of the sulphide of only one metal, namely the same as the
metal it decorates: silver sulphide (acanthite Ag2S) for silver
objects and mixtures of copper sulphides (chalcocite Cu2S,
digenite Cu9S5 and covellite CuS) for copper-based alloy
objects. Intentional use of binary silver-copper sulphide
niello (stromeyerite AgCuS) is assumed to have started
only at the end of the 5th century AD (Moss, 1953; Dennis,
 et al.     et al.,
       
Recent studies have proved that silver-copper sulphide niello
(reaching the composition of stromeyerite) was already
being used in Roman times (Mozgai et al.
The studied buckles were decorated with silver-copper
        
µ-XRD measurements proved the presence of stromeyerite
(AgCuS), digenite (Cu9S5) and metallic silver. The niello
inlays of the buckle from Gáva are also silver-copper sulphides
with sporadically detected lead and tin contents, which was
interpreted as niello prepared from debased silver (Horváth
et al.       
the 5th century AD proved the presence of mixed silver-copper
     et al.  
et al.
silver objects, reaching even the composition of pure copper
sulphide, has not yet been described.
The use of silver-copper sulphide niello by the craftsmen
can be threefold (Mozgai et al.   
use, when the goldsmith was not aware of the copper content
of the silver alloy used for the preparation of the niello;
(ii) intentional use, when the silversmith was aware of the
variable copper content of the silver alloy available to him,
but did not care; and (iii) technological innovation, when the
silversmith intentionally prepared a starting silver-copper
alloy using a recipe to gain either technological or economic

The short supply of metals in the period could have led to
a wider use of cheaper materials and also to a more frequent
      

       
sulphides look exactly the same. The craftsman clearly felt
no need to distinguish between them and he did not bother to

The presence of metallic silver in the niello inlays can be
interpreted as not all the silver metal reacted with sulphur
during preparation or the niello decomposed at elevated
temperatures, as silver-copper sulphides start to decompose
to elemental silver in an oxidising atmosphere before


et al.
Previous studies on objects decorated with silver-
copper sulphide niello from the early medieval ages
(5thth century) were interpreted as their niello not
 
     
malleable at room temperature, and even more when
heated; experiments proved that it is possible to inlay
niello in solid form, softening them a little by heating
      
        
the literature for the application of silver-copper sulphide
niello in solid form: either in powder form or as compact
strips. In the case of the powder form the craftsman has to


      
and to reach a compact polishable surface (Moss, 1953;
   et al.   et al. 


     
   
rubbing heated niello particles into the recesses during
      
become completely compacted together and did not leave
a homogeneous sulphide inlay (Stemann-Petersen, 1995;

buckles do not look even and compact enough.
The patches of mercury and gold on the surface of the
niello inlays are the remnants of gilding, during which
mercury or gold amalgam spread over the surface of the
niello, as well as reacting with the material of the niello
forming silver amalgam.
5.3 Gilding
The buckles were extensively gilded with a relatively thick
gold layer. Mercury was detected in the gilding of the
     
on objects from the 5th century AD have also proved the
  et al. 
The buckle from Gáva was also decorated with this type of
gilding (Horváth et al.
Fire gilding was most probably invented in China in the
4th

mercury and the resulting gold amalgam was rubbed on to the
cleaned metal surface, after the object was heated for a few


avoid any overheating of the object: if silver is overheated,
the gold will discolour or even disappear into the substrate.


porous, matte gilded layer will form, which then needs to
be burnished. This technique is still used in Nepal (Oddy,
        
is mentioned as a rare and costly method by Pliny in the
1st century AD, but became the standard method of gilding in
the 3rd–4th centuries AD and continued in use throughout the
Migration Period and medieval Europe until the invention
of electroplating in the mid-19th  


IANSA 2021 ● XII/1 ● 45–67
Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

to the metal surface to be gilded and then lay pieces of gold
leaf on top. The gold leaf dissolves in mercury creating a
gold amalgam in situ, after which the object is heated and
 


Fire gilding superseded gold-plating during the second
half of the 5th century AD (Mozgai et al. 
et al.
         
        
sophisticated gilding method indicating the development of
goldsmithing skills during the 5th century AD.
5.4 Garnet inlays

garnets, were widespread during the Hellenistic, Roman and
       
the archaeological material of the Carpathian Basin, garnet
inlay decoration was a characteristic feature over around
three centuries, from the Hunnic Period through the age
of the Gepidic and Langobardic Kingdoms until the Avar

inlays have come into focus since the end of the last century.

or at one-time, mine districts facilitated their increasingly
detailed geochemical characterisation (recently: Schmetzer
et al.et al.,
       
   
and trace elements) with similar datasets of recent geological
samples has proved to be the key to the localisation of
potential geological sources.
The garnets in the buckles are almandine, and on
rare occasions intermediate pyrope-almandine, from the
pyralspite series. The chemical composition of the garnet
slabs was compared to the chemical composition of garnets
from those deposits which were certainly known and used
in the Migration Period, as attested by the analyses of other
contemporaneous objects. The chemical composition and the
characteristic inclusion assemblages revealed that European
deposits can be excluded as possible sources (Figure 11).
  
(Cluster A) and to a heterogeneous group (Group X)
requiring further division (Gilg et al.   
         
and only a few garnets belong to Group X. Contrarily, the
inlays on buckle ZsD are mainly Group X garnets and only
a few Cluster A garnets are present (Figure 11). The garnet
inlays on the buckle from Gáva belong to both Cluster A and
Group X (Horváth et al.
Cluster A garnets, generally comprised of chromium-
bearing almandines originating most probably from Southern
et al.et al.
     
Carpathian Basin, applied from the beginning of the Hunnic
Period (Horváth et al.
with a higher magnesium content, originate from the placer
Figure 11.  
 et al.et al.
represents garnets with variable chemical and gemmological characteristics that derive from various, unknown deposits and cover possible new clusters:


IANSA 2021 ● XII/1 ● 45–67
Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin

  et al.
Gilg et al.
suggesting that a number of primary sources may be
involved, and the group comprises, most probably, several
clusters (Gilg et al.     
   

et al.et al., in
preparation). Based on the chemistry, garnets from Ratnapura
(Sri Lanka) and Elahera (Sri Lanka) deposits might be
 
investigations are in progress on the mineral inclusions of
the garnets of these two deposits and further potential source
materials (Gilg, personal communication). Most of the
garnets from buckle ZsD may originate from a third cluster
based on the chemical composition and especially on the
characteristic mineral inclusions (Figure 9C–D; Figure 11),
but investigations on geological samples are required to
prove this hypothesis. Prospective measurements of the trace
   
        
minor element compositions.
Group X and Cluster A garnets were predominant all over
Europe during the 5th century AD. As Sri Lanka and Southern
India are close to each other geographically, most probably
their garnets were transported via common long-distance
        
originating from Northern India, were observed on the buckles.
Northern Indian garnets became commonly used only from
th century AD (Gilg et al.
6. Conclusion
Three polychrome animal style silver buckles, dated to the
second half of the 5th century AD, were analysed in order to
determine the elemental composition of their metal alloys and
to explore techniques of their manufacture and decoration
(gilding, niello and garnet inlays). Non-destructive and
non-invasive analytical methods, such as handheld XRF,
SEM-EDX and µ-XRD, were successfully used, while their
limitations – such as using a special preparation technique
needed for the SEM-EDX analysis of mounted garnets;
in situ microtextural and mineralogical analysis of the niello
inlays, and geometric and calibration limitations – were also
kept in mind.
The buckles were manufactured from high-quality silver,
but a gradual decrease in the silver quality is evident towards
the end of the 5th century AD. The elevated lead and zinc
contents indicate that silver was intentionally alloyed with

     
        
       
       
shortage of raw material caused mainly by the decrease of
primary mining.
Each buckle is richly decorated by chip-carving, gilding,
niello and garnet inlaying. The presence of mercury indicates
   
composed of mixed silver-copper sulphides with relatively
high copper contents, even reaching the composition of pure
copper sulphide. Copper sulphide niello on a silver object has
not yet been reported before. The presence of metallic silver

the niello’s surface suggest that it was made by an unskilled
craftsman. Based on their chemistry and mineral inclusions,
the almandine garnets of the buckles most probably derive
from Southern India and Sri Lanka.
It is unequivocal from the similarity of the elemental
composition of its silver alloy and garnet inlays to the other
parts of the buckle that the tongue with bird’s head belonged
to buckle UP originally. The tongue with bird and boar heads
could have been the accessory of another buckle.
The buckles could not be related to the work of a single
goldsmith, or workshop; it is much more likely that these
are products from workshops that operated in the same
region and followed, more or less, similar practices. The
localisation of the workshops remains an open question, but
the late Roman metalwork in the provinces along the limes
must have had an impact. Based on the prevalence of the
        
hypothetically localise the workshops near the centres of
barbaric power (Germanic tribal kingdoms) in the former

remains to be done in the light of further evidence.
Acknowledgements
       
 

Tóth (IGGR RCAES ELRN), Máté Szabó (IGGR RCAES
ELRN), Péter Németh (IMEC RCNS ELRN), Zsuzsanna
Hajnal ((Hungarian National Museum, Budapest), Gergely
Kovaliczky (Janus Pannonius Museum, Pécs) and Marianna
Dági (Museum of Fine Arts, Budapest).
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Viktória Mozgai, Eszter Horváth, Bernadett Bajnóczi: Possibilities and Limitations of Non-Invasive Analytical Methods in the Examination
of Garnet- and Niello-Inlaid Precious Metal Objects – Case Study of Three Polychrome Animal-Style Silver Buckles from the 5th-Century Carpathian Basin
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treasure of Late Roman silver plate: preliminary report. Journal of Roman
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Thermal Analysis and Calorimetry
... Scanning electron microscopy with energy-dispersive X-ray spectrometry (SEM-EDX) was used to determine the chemical composition of the garnet inlays. As garnets are non-conductive materials, a special sample preparation was applied earlier (Bendő et al., 2013;Mozgai et al., 2021a). However, using the low vacuum mode during SEM-EDX measurements, garnets could be analysed without any special sample preparation. ...
... This composition corresponds well with the general trend that the beginning of the 5 th century AD is characterised with high-quality silver alloys with low Au, Pb, Zn and varying Bi content similar to late Roman silver alloys (Hughes and Hall, 1979;Lang et al., 1984;Cowell and Hook, 2010;Doračić et al., 2015;Lang and Hughes, 2016;Greiff, 2017;Vulić et al., 2017;Mozgai et al., 2020;2021b;Troalen and Lang, 2022). However, a gradual debasement of silver alloys occurred towards the end of the 5 th century (Horváth et al., 2019; Mozgai et al., 2019;2021a). Comparing our results to gilded silver plates from other Hunnic-period sacrificial deposits, the silver plate from Nyergesújfalu has a similar silver and copper content to the silver plates from Telki-Anna-lak (Ag: 93.4-97.6 wt%; Cu: 0.9-2.2 ...
... Mercury was detected in the gilded areas by hXRF and SEM-EDX measurements as well, indicating the use of fire gilding (Figure 6). Previous studies on the objects from the 5 th century AD have also proved the use of fire (or mercury) gilding (Craddock et al., 2010;Horváth, 2013;Szenthe et al., 2019;Mozgai et al., 2021a). Fire gilding was most probably invented in China in the 4 th century BC, and it then became the standard method of gilding in the 3 rd century AD and continued in use throughout the Migration Period and medieval Europe until the invention of electroplating in the mid-19 th century (Lechtman, 1971;Lins and Oddy, 1975;Oddy, 1981;1988;2000). ...
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Near Nyergesújfalu (Komárom-Esztergom County, Hungary), objects of a Hunnic-period sacrificial assemblage were found in 2021. The Hunnic period assemblage contains fifteen items altogether: four gold lunular mounts, six cellwork-decorated gold oval mounts, two cellwork-decorated gold suspension rings, two gold buckles and fragments of a scale-patterned gilded silver plate. The present study aims to determine the elemental composition of the metal alloy of the Hunnic-period objects and characterise the decoration techniques (gilding and garnet inlays) by using optical microscopy, handheld X-ray fluorescence spectrometry (hXRF) and scanning electron microscopy with energydispersive X-ray spectrometry (SEM-EDX). The gold objects, including their small parts such as the rivets of buckles and lunular mounts, sockets and filigree, were manufactured from a relatively goodquality gold alloy (>80 wt% Au). The fragments of the scale-patterned silver plate were manufactured from a high-quality silver alloy (>94 wt% Ag), similar to late Roman silver alloys characterised by high Ag content, and was decorated with fire (mercury) gilding. The garnets used for inlays are almandine and intermediate pyrope-almandine garnets. Based on their chemistry, the garnets belong to Group X and probably originate from the placer deposits of Sri Lanka.
... However, a gradual debasement of silver alloys occurred towards the end of the 5th century, with an increase in the use of alloying elements, such as Cu, Pb, Zn, and Sn. The elevated Au content also implies the recycling of gilded objects (Horváth et al., 2019a;Mozgai et al., 2019Mozgai et al., , 2021b. The differences in the silver contents of the various parts of the buckle's tongue may suggest that it was manufactured from a very heterogeneous silver-copper alloy. ...
... This innovative solution probably targeted the adaptation of golden cloisonné cellwork on large-sized silver castings. Similar artefacts with golden cloisonné embedded in (gilded) silver are known only from the late 5th and mid-6th centuries AD, such as a belt buckle from an unknown Hungarian site (Mozgai et al., 2021b, their Fig. 1/c, 48) and an S-shaped brooch from the Langobardic period cemetery of Vörs (Hungary) (Horváth 2012b, her Fig. 1/i, 232-233). ...
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Fifty years after the discovery of the Regöly grave, the emblematic Hunnic period archaeological assemblage from Hungary, an extensive scientific investigation was performed on the polychrome dress accessories of the high-status woman, often referred to as the "Princess of Regöly", buried there. The multi-instrumental analyses aimed to characterise material and technological aspects of the gemstone-inlaid artefacts (a set of a pair of bowbrooches and a belt buckle), i.e., the manufacturing and decorative techniques as well as the chemical and mineralogical compositions. The non-destructive and non-invasive gemmological and geochemical analyses applied optical microscopes, handheld XRF, SEM-EDX and Raman microspectrometer. This study provides the first comprehensive examination of the Hunnic period polychrome jewellery, and highlights the potential of combining surface and subsurface analyses to specify garnet provenances. It presents the first evidence of use of antique and early medieval garnet sources during the early Migration period. The findings enhance understanding of the garnet supply chain and trade network, the production organisation and potential workshop connections. Significant differences of the brooches and the buckle reveal varying levels of luxury among the elite, providing insight into the social context of the polychrome jewellery associated with the "Princess of Regöly".
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Raman spectroscopy and laser ablation‐inductively coupled plasma‐mass spectrometry were used to characterize the chemical composition of 34 red garnet beads from Lower Nubian sites, dated between about 3200 BCE and 600 CE. All beads from the A‐Group to the Meroitic period feature a similar calcium‐poor almandine composition (69%–78% almandine, 15%–22% pyrope, 2%–6% grossular, 3%–9% spessartine), which differs from other calcium‐poor almandine garnet types, sourced mostly from Indian deposits in Antiquity. The Nubian beads constitute a new garnet type, named “cluster I”, featuring high yttrium (180 to 1205 ppm), moderately low chromium (13–70 ppm), and high scandium (119–213 ppm) concentrations. Their compositions match with previous and two new analyses from two alluvial garnet deposits, Wadi El‐Haraz and Wadi Abu Dom, near the Fourth Cataract of the Nile in Upper Nubia, about 670 km as the crow flies from the Lower Nubian graves. Garnet trade between the Bayuda desert and Lower Nubia sites, and possibly even Egypt, flourished for almost four millennia. Northeastern Africa is the cradle for the oldest use of a gemstone that is harder than quartz—the red almandine garnet. A Post‐Meroitic bead, the youngest in the assembly, displays an unusual faceting, a diamond tipped drill hole, excellent polish, distinct short‐ and long‐prismatic colorless mineral inclusions, and a calcium‐ and manganese‐poor pyrope composition. This suggests that it was not of a local, Nubian, production, but imported, most probably from a South Asian site.
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The late Roman silver quadripus from Kőszárhegy (Fejér County, Hungary) is the only known silver folding stand from the Late Roman Imperial Age, dated to the fourth century AD. Archaeological evidence indicates that the quadripus is closely related to the Seuso Treasure. Elemental composition and lead isotope analyses of samples taken from the various parts of the folding stand were performed by using LA-QICP-MS and MC-ICP-MS methods in order to determine the provenance of raw material used and the production technology. The silver quadripus consists of rather pure silver (92.5–96.5%) intentionally alloyed with copper. The different trace element composition (Bi, Au, Pb) of the various parts (base, lower part, griffin, upper part, finial, cross bands) indicates the use of different silver batches implying that the various parts were made separately, and then soldered together with hard solders. The same parts of the two original feet are very similar regarding their elemental composition and lead isotope ratios suggesting series production. The nearly constant gold and lead contents of the object indicate that not re-used or re-melted, but primary, cupelled silver was used for manufacturing. The lead isotope ratios of the quadripus cover a quite narrow range (²⁰⁶Pb/²⁰⁴Pb = 18.514–18.717; ²⁰⁷Pb/²⁰⁴Pb = 15.645–15.667; ²⁰⁸Pb/²⁰⁴Pb = 38.592–38.817). Comparing our results to the lead isotope data of the European lead-silver ores, and taking into consideration the archaeological evidences, the silver used for manufacturing the quadripus could come from the Balkan region.
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This study details the non-destructive chemical analysis of composite silver objects (ewers, situlas, amphora and casket) from one of the most significant late Roman finds, the Seuso Treasure. The Seuso Treasure consists of fourteen large silver vessels that were made in the fourth–early fifth centuries AD and used for dining during festive banquets and for washing and beautification. The measurements were systematically performed along a pre-designed grid at several points using handheld X-ray fluorescence analysis. The results demonstrate that all the objects were made from high-quality silver (above 90 wt% Ag), with the exception of the base of the Geometric Ewer B. Copper was added intentionally to improve the mechanical properties of soft silver. The gold and lead content of the objects shows constant values (less than 1 wt% Au and Pb). The chemical composition as well as the Bi/Pb ratio suggests that the parts of the composite objects were manufactured from different silver ingots. The ewers were constructed in two ways: (i) the base and the body were made separately, or (ii) the ewer was raised from a single silver sheet. The composite objects were assembled using three methods: (i) mechanical attachment; (ii) low-temperature, lead-tin soft solders; or (iii) high-temperature, copper-silver hard solders. Additionally, two types of gilding were revealed by the XRF analysis, one with remnants of mercury, i.e. fire-gilding, and another type without remnants of mercury, presumably diffusion bonding.
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Handheld X-ray fluorescence spectrometry is a widely used analytical method for the determination of the chemical composition of archaeological metal objects. Beside its several advantages (fast, cheap, portable, non-destructive, non-invasive, no sampling or special sample preparation is needed, etc.), the method has some limitations as well (surface method, geometric limitations, inhomogeneity within the objects, calibration, standardisation, etc.), which are needed to take into consideration during data evaluation and interpretation. In this present study, the possibilities of the handheld XRF are demonstrated on the example of 3rd-4th century AD Roman silver platters from the collection of the Hungarian National Museum (platters and the basin from the Seuso Treasure, three platters from the Sava river, two bowls from Esztergom and one plate from Nagyberki-Szalacska). The vessels were manufactured from high-quality silver (94.3-98.9 wt%), typical for the late Roman period, intentionally alloyed with copper (0.3-4.0 wt%). The rather low and constant gold and lead contents (0.4-1.1 wt% Au; 0-0.6 wt% Pb) indicate that primary cupelled silver, and not secondary remelted/reused gilded scrap silver was used for manufacture. The platters can be categorised based on their Bi/Pb and Au/Ag ratio. The different groups indicate the use of different silver ingots. Based on the presence of mercury, Seuso and Geometric Platters were decorated with fire gilding.
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Outstanding garnet beads were found recently in an elite tumulus dated to the fourth century AD and located at the cemetery of Hagar el‐Beida in the Upper Nubian Nile Valley region. Whereas contacts of Northeast Africa with South Asia have just been proven through analysis of glass beads found in Nubia and dating to the time of intensive Indian Ocean trade, scientific evidence for Nubia's link with the regions to the west was lacking. Laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) was used to determine the elemental composition of three garnet beads to gain information about their type and origin. Additionally, we analyzed twelve garnets from two nearby alluvial placer deposits. While the garnet beads are inclusion‐free Cr‐poor and Ti‐rich pyropes related to alkaline mafic volcanic rocks, the local garnet deposits are shown to be inclusion‐rich almandines and thus unrelated to the investigated Nubian beads. Detailed comparison of data from Merovingian cloisonné jewellery and all known sources of the Cr‐poor and Ti‐rich pyropes shows identical ranges of elemental contents. The source of raw materials for the beads found in Nubia has been not identified with certainty yet, but sources in Portugal and Nigeria are suggested and a connection is shown to similar garnets from Merovingian contexts.
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L’existence à l’époque gréco-romaine d’un grand commerce, principalement maritime mais aussi terrestre, entre le monde indien et la Méditerranée est bien attestée par les textes ainsi que par des indices archéologiques, davantage, en ce qui concerne ces derniers, pour l’Inde que pour l’Occident (Suresh, 2004, 2007). Néanmoins, les sources écrites pouvant témoigner de la continuité de ces échanges durant le haut Moyen Âge sont des plus maigres, du moins du côté occidental, à l’exception de la Topographie chrétienne de Cosmas Indicopleustès (Wolska- Conus, 1973) qui prouve que des textiles précieux, des épices et des gemmes parvenaient toujours en Occident au vie siècle (Doehaerd, 1971). Les sources écrites indiennes et perses, puis arabes, renseignent davantage (Banaji, 2012 ; Christides, 2015). Mais, hormis quelques restes de tissus, conservés dans les trésors d’églises ou issus de fouilles exceptionnelles, comme celles des sépultures mérovingiennes de la basilique de Saint- Denis, les témoins matériels de ces échanges demeurent très rares. Grâce aux fouilles récentes menées en Europe de l’ouest et au développement des études en laboratoire, cependant, il est maintenant possible d’établir qu’au début del’époque mérovingienne, on a utilisé en Gaule des micro-perles de verre de type « indo-pacifique » (Pion et Gratuze, à paraître) et employé massivement dans l’orfèvrerie cloisonnée des grenats provenant d’Inde et du Sri Lanka (Ceylan), ce qui démontre la survivance, au moins jusqu’à la fin du vie siècle, d’échanges suivis entre le subcontinent indien, le monde méditerranéen et l’Occident mérovingien.
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X-ray diffraction (XRD) is a widely used method to specify the mineralogical composition of archaeological artefacts, e.g. the material of inlays or corrosion products of metal objects. Laboratory micro-XRD instruments, like the RIGAKU DMAX RAPID II micro-X-ray diffractometer (μ-XRD), can be used instead of conventional X-ray (powder) diffraction analysis if sampling is not or just limitedly allowed due to e.g. the high value of the archaeological object. In these cases, in situ non-destructive measurements directly on the object or on the detached, small-sized samples are preferred. The possible application of this laboratory micro-XRD instrument in the analysis of archaeological metal objects is demonstrated on the example of three case studies. In order to reconstruct the manufacturing technique of Roman-period niello (black metal sulphide), niello inlays of a late Roman silver augur staff were analysed. Due to the uniqueness and high value of the well-dated and intact object, only non-destructive analytical methods were permitted. Based on the SEM-EDS and μ-XRD results, five niello types were found on the object: pure silver sulphide and different silver-copper sulphides (with silver/copper ratio from 3:1 to 1:1). The object was originally decorated with these diverse niello inlays indicating that silver-copper sulphide niello, even stromeyerite (AgCuS), was used by the Roman craftsmen two-hundred years earlier (last third of 3 rd century AD) than the previous studies indicated (end of 5 th century AD). Corrosion products of a large-sized, late Roman copper cauldron were examined in order to characterise the burial environment. The corroded metal samples taken from the cauldron were analysed in cross section, layer-by-layer, using electron microprobe and μ-XRD analyses. Different corrosion products were identified: copper oxide (cuprite) and copper carbonate (malachite) are the products of passive corrosion indicating burial in a well-aerated, calcareous soil environment, whereas copper chloride (nantokite), copper hydrochloride (paratacamite/atacamite) and copper sulphate (brochantite) are the products of active corrosion forming after excavation. Material and corrosion products of gold and gilded silver objects of the Hunnic Period were analysed by using electron microprobe and μ-XRD analyses. The surface of the high-purity gold objects is covered by a very thin reddish layer, which is a tarnish composed of mixture of gold-silver sulphide corrosion products. The silver objects were completely mineralised into silver sulphobromide and bromian silver chloride (embolite), typical corrosion products of silver alloys buried in soil environment (rich in organic matter). No copper corrosion products were detected indicating that the silver objects were most probably manufactured from high-purity silver alloy.
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The archaeological site of Arikamedu, located in Tamil Nadu State on the east coast of India, was the centre for many centuries of a significant bead-producing industry. Beads were made of both glass and stone, including garnet, but the source of the garnet rough material has not been confirmed. To probe this question, garnet beads found at Arikamedu were compared with rough material from the Garibpet deposit, located approximately 640 km away in Telangana State, east of the city of Hyderabad, India. Samples from the two localities exhibited substantial correlation with respect to average composition, trace-element contents, chemical zoning of major and minor elements, inclusion assemblages and zoning of inclusions between the rims and cores of the crystals. Chemically, the stones were almandine rich (averaging 81.0% almandine, 11.5% pyrope, 3.3% spessartine and 1.5% grossular), with pronounced zoning for Mn and Mg. Zoning of trace elements also was observed, especially for Y, P and Zn. The most characteristic aspects of the inclusion pattern were sillimanite fibres that were concentrated in a zone between an inclusion-rich core and an inclusion-poor rim. In combination, the microscopic observations, identification of the inclusion assemblage, and chemical analyses established that the rough material used historically in the Arikamedu area to produce garnet beads originated from the Garibpet deposit. Furthermore, the results suggest that existing schemes for classifying historical garnets require additional refinement.
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The paper outlines the results of some of the preliminary investigations carried out on a late Roman hoard of luxurious silverware. They have yielded valuable data on the manufacturing technology and the state of the objects. This work is part of a complex and long-term programme of conservation and restoration of the hoard which will also include a detailed technological examination of each individual object.
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Niello, a bluish black metal sulphide, was widely used for decoration of metal objects by artisans of the Roman Empire. Our knowledge, however, concerning the exact Roman-period niello technique, the appearance of binary silver–copper sulphide niello-decorated silver objects in particular is very scarce. An extensively nielloed silver augur staff (lituus), a unique find from the territory of the Roman Empire, was analysed non-destructively with SEM–EDS and micro-X-ray diffraction techniques. Five niello types were identified, their chemical compositions range from silver sulphide (Ag2S, acanthite) to binary silver–copper sulphide of Ag:Cu ratio 1:1 (stromeyerite). The augur staff decorated with such heterogeneous niello inlays is the first object ever analysed in this manner. Mineralogical and archaeological arguments link niello heterogeneity to the primary production of the object rather than to any post-production repair. Texture-related mineral phase observations allow closer insight into Roman niello technology. The variable copper content is not to be attributed to some technological innovation. The silversmith simply employed not only silver, but in order to make up for the shortage of silver, also differently debased silver, possibly scrap materials for producing niello. Both production (260–280s AD) and burial (early fourth century AD) periods of the lituus are well-dated, and the object was excavated from an undisturbed sarcophagus. Therefore, our data imply that silver–copper sulphide niello reaching the composition of stromeyerite was used by the Roman craftsmen 200 years earlier than previously studied finds had indicated.
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An Early Byzantine almandine garnet engraved with a Christian motif and dated to the late sixth to eighth century offers insight into trade practices in antiquity. The gemstone was characterized by a combination of nondestructive analytical methods including electron microprobe, portable X-ray fluorescence, Raman spectroscopy, and optical microscopy. The chemical composition and zoning, in combination with the inclusion assemblage and the distinct distribution of inclusions between an inclusion-rich core and an inclusion-poor rim, indicated that the sample most likely originated from the large Garibpet deposit in Telangana State, India. The Byzantine intaglio thus furnishes evidence of garnet transport from the eastern Indian coast to the Mediterranean world during Early Medieval times. In so doing, it supports the interpretation of a sixth-century text by the Greek merchant and traveler Cosmas Indicopleustes, which describes the export of "alabandenum," a reference to garnet, from harbors on the southeast Indian shore along the ancient Maritime Silk Road. This idea is further buttressed by considering that garnet from the Garibpet deposit was used for bead production at the archaeological site of Arikamedu, one of the historical ports on the Coromandel Coast in southeast India. Conversely, a comparison with properties of the two predominant types of almandine used in Merovingian cloisonné jewelry shows that the characteristic mineralogical features and therefore the sources of these garnets set in Early Medieval jewelry were different.
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The hoard of silver plate known as the Vinkovci treasure (or the Cibalae treasure, after the Roman name for the town) was discovered on March 23, 2012, during rescue excavations in the town of Vinkovci ( Colonia Aurelia Cibalae ) in the Vukovar-Srijem county of E Croatia (fig. 1). It is one of the most significant late Roman discoveries of the new millennium, and the first major 4th-c. A.D. assemblage of silver plate to be unearthed for at least half a century (the Seuso treasure was probably found in the late 1970s, and although new pieces of the Kaiseraugst treasure emerged in the 1990s the original discovery was made in 1961). This interim report on the treasure is based upon the results of research conducted by the authors in the 4 years that have passed since it came to light.