Non-destructive μXRF analysis of glass and metal objects from sites in the Libyan pre-desert and Fazzan

2015 ◽  
Vol 46 ◽  
pp. 15-34 ◽  
Author(s):  
C.N. Duckworth ◽  
A. Cuénod ◽  
D.J. Mattingly

AbstractThis paper reports on the non-destructive analysis of 42 samples of copper alloy and glass from sites in Libya, using semi-quantitative μXRF, carried out as part of the work of the Trans-Sahara Project funded by the European Research Council. These are among the first chemical analyses to be performed on metals and glasses of any period found in Libya, and the results – though preliminary – raise some interesting possibilities. In particular, we discuss some possible indications with regard to the practice of recycling glasses, as evidenced through heterogeneous, malformed glass beads with variable quantities of lead. A glass mirror from Ghirza was also found to be backed in lead, and was probably the result of a glass-making technique still practised in recent times in India. The metal analysis has revealed evidence of a pre-Islamic trade in brass in the northern Sahara, as well as showing the presence of objects made from the mixing of different types of scrap metal, a process probably taking place at the Garamantian metalworking site of Saniat Jibril among other locations. The importance of further analysis of available Libyan and other North African metal artefacts and glasses for the contextualisation and extension of these findings is emphasised.

Heritage ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 400-407 ◽  
Author(s):  
Bethany Hampshire ◽  
Kevin Butcher ◽  
Katsu Ishida ◽  
George Green ◽  
Don Paul ◽  
...  

Debasement of silver Roman coins is a well-known phenomenon and understanding the quality of ancient silver coinages can provide an idea about the underlying fiscal condition of the issuing states. These coins are made from a silver-copper alloy, the surfaces of which were deliberately enhanced at the mints by a process of surface-enrichment to give them the appearance of being made of pure silver. Therefore, any surface analysis would provide a composition of the silver-copper alloy that would not be representative of the original alloy from which the coin blank was made; the result would be too high in silver. However, the bulk of the sample, the interior, should provide a composition that is true to the original alloy. Elemental analysis using negative muons has been used to provide a depth dependent compositional, completely non-destructive analysis of a silver-copper alloy denarius of the empress Julia Domna datable to 211–217 CE. The composition of the coin, beyond the surface enrichment layer, is 51 ± 1.8 % copper and 49 ± 1.9% silver, taken at a muon depth of 402 ± 61 µm. The surface enrichment layer is approximately 190 µm thick.


Author(s):  
Jingjing Xia ◽  
Xiayu Du ◽  
Weixin Xu ◽  
Yun Wei ◽  
Yanmei Xiong ◽  
...  

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