An overview of the use of the elemental composition of gold in the study of manufacturing technologies for objects as well as of the provenance of the metal is given. Depending on the objects, techniques based either on atomic physics or on nuclear physics and mass spectrometry are required to answer the questions surrounding the process of metalworking in the past. Several archaeological examples covering different periods of time and involving diverse analytical techniques are presented here. With those examples we illustrate the main research questions on precious objects and coins and show how far the elemental analysis of the objects can reveal the way they were made and provide information on the origin of the gold.

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From the study of coins and casted simple objects to intricate jewellery comprising many diverse parts joined together, analytical queries on ancient goldwork concern the description of the manufacturing techniques, the identification of the authenticity and the localisation of the exploited sources of gold. Through the examination of the objects by x-ray radiography and the non-destructive elemental analysis of the gold alloys -by XRF, SEM-EDX, PIXE and SR-XRF, x-ray based techniques have always played an important role in the study of cultural heritage and, in particular, of goldwork.The aim of this article is to give a short overview of the use of the most established scientific-based techniques in the study of goldwork, with special outlining on the limitations, advantages and applications of x-ray based techniques. Two applications illustrate both the potential of examination techniques to identify the authenticity of gold jewellery and the importance of combining examination techniques and elemental analysis to describe the fabrication stages of goldwork. At last, a third example shows the significant socio-economical assumptions developed by determining the characteristic trace elements of gold when coinages are considered.

Forty-two mosaic coloured/opaque "glass" tesserae from three sites (Milan, Italy; Durrës, Albania; Hierapolis, Turkey) situated in the Western and Eastern parts of the Roman/Byzantine Empire, dated between the 5 th and the 9 th centuries, were studied by optical microscopy, SEM-EDX and Raman microspectroscopy in order to investigate the nature of their pigments and opacifiers as well as the microstructure of glass ceramic materials. The Raman signatures of glass matrix and phases dispersed in the soda-lime glassy matrix showed the presence of six opacifiers/pigments. The use of soda ash glass in the tesserae from Durrës (post 8 th c.) allows refining the mosaic debated chronology. The use of soda ash matrix glass together with the presence of calcium antimonates (Ca 2 Sb 2 O 7 and CaSb 2 O 6 ), pyrochlore solid solution/Naples' yellow (PbSb 2-x-y Sn x M y O 7-δ ) and cuprite (Cu 2 O) or metallic copper (Cu°) in many samples show the technological continuity in a Roman tradition. However, the presence of cassiterite (SnO 2 ) and quartz (SiO 2 ) in one sample from the beginning of the 5 th century, diverging from Roman technology, offers a chronological marker to identify newly (not re-used) produced tesserae. Graphical abstract HighlightsOpaque/coloured glass mosaic tesserae exhibit a glass ceramics microstructure.The innovative use of cassiterite (SnO 2 ) and quartz (SiO 2 ) in 5 th century tesserae is evidenced.The technological innovations went alongside the continual use of Roman recipes (calcium antimonate and yellow pigments). NoveltyThe first use of cassiterite and quartz in the beginning of the 5 th c. as well as the use of calcium antimonates after Roman times in the tesserae produced ex novo with mixed glasses were demonstrated.

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