Lombardo T.,Laboratory for Conservation Research |
Grolimund D.,Paul Scherrer Institute |
Kienholz A.,Office for Spatial Development |
Hubert V.,Laboratory for Conservation Research |
Worle M.,Laboratory for Conservation Research
Microchemical Journal | Year: 2016
The construction of an underground parking garage in the centre of Zurich (Zurich Opéra Parking, Switzerland) unearthed remains of seven Neolithic settlements from the 4th and 3rd millennium BC. The greatest number of prehistoric founds were retrieved from the 3175 BC layer (Horgen culture). Among the findings, several thousand flint-stone fragments were excavated. According to archaeologists' interpretation, based on wear patterns, some of them were certainly used to produce fire. Remarkably, a limited number of the flint-stones revealed additional characteristic metallic traces of potential anthropogenic origin. The contingent relation of these fragments to fire production was to be elucidated. An advanced, non-destructive micro-analytical approach was needed to characterise these unusual features. Seven flints were thus analysed by laboratory-based μ-XRF and RAMAN spectroscopy complemented by two-dimensional microscopic chemical imaging based on combined μ-XRD-μ-XRF analysis using micro-focused synchrotron radiation. The complementary results showed that all flint-stones, even the most doubtful, presented abundant traces of Fe-sulphide, which were almost exclusively pyrite. Only sporadic indications towards the presence of trace amounts of marcasite and chalcopyrite were found. Furthermore, during the excavation, Fe-sulphide ore pieces were found in the same layer as the flint-stones. Geologically, these iron nodules appeared to be non-native to the setting in which they have been observed. The Fe-sulphide ore was also undoubtedly recognised as pyrite, indicating its potential use, conjointly with the flints, to kindle fire in a more efficient manner by the Neolithic populations at Lake Zurich more than 5000. years ago. © 2015 Elsevier B.V..
Karampelas S.,Gubelin Gem Laboratory |
Worle M.,Laboratory for Conservation Research |
Hunger K.,Laboratory for Conservation Research |
Lanz H.,Collections and Documentation
Journal of Raman Spectroscopy | Year: 2012
The gems that adorn two golden chalices from Einsiedeln Abbey (Switzerland) crafted in 1609 and 1629 were investigated using Raman spectroscopy. The results were also compared with those obtained by other non-destructive means such as microscopy and energy-dispersive X-ray fluorescence. The chalice made in 1609 was adorned with 16 corundum (15 rubies and 1 sapphire), four garnets (two almandine and two grossular), seven quartzes (six amethysts and one citrine) and one peridot (forsterite olivine). All pearls of this chalice were found to be from a saltwater mollusc. The chalice crafted in 1629 was adorned with 23 diamonds. Compilation of all the results does not exclude that the stones mounted to the chalices are of 'oriental' origin. However, more research needs to be done by additional spectroscopic means to shed more light on their origin. Copyright © 2012 John Wiley & Sons, Ltd.