scholarly journals Revealing ancient gold parting with silver and copper isotopes: implications from cementation experiments and for the analysis of gold artefacts

2021 ◽  
Vol 13 (9) ◽  
Author(s):  
Daniel Berger ◽  
Michael Brauns ◽  
Gerhard Brügmann ◽  
Ernst Pernicka ◽  
Nicole Lockhoff
Keyword(s):  
Trace Element ◽  
Isotope Fractionation ◽  
Copper Alloys ◽  
Pure Gold ◽  
Copper Isotopes ◽  
Gold Silver ◽  
Analytical Proof ◽  
Gold Refining ◽  
Isotope Systematics ◽  
Silver Isotope

AbstractGold parting enabled the production of very pure gold for various purposes from the sixth century BC onwards, but analytical proof of this pyrotechnical process is difficult. We describe a new analytical approach for the identification of purified gold combining silver and copper isotopic with trace element analyses. Parting experiments were performed with gold-silver-copper alloys using the classical salt cementation process to investigate potential silver and copper isotope fractionation and changes in trace element concentrations. In addition, we provide the first comprehensive dataset of silver isotope ratios of archaeological gold objects from the Mediterranean and Central Europe to test whether or not gold refining can be identified on the basis of isotope systematics. The results show that very heavy silver and copper isotopic compositions are clear evidence for parted gold, but that the application of copper isotopes might be limited.

Types of Gold, Types of Silver: The Composition of Precious Metal Artifacts Found in the Royal Tombs of Ur, Mesopotamia

2018 ◽  
Vol 108 (1) ◽  
pp. 100-131
Author(s):  
Andreas Hauptmann ◽  
Sabine Klein ◽  
Paola Paoletti ◽  
Richard L. Zettler ◽  
Moritz Jansen
Keyword(s):  
Copper Alloys ◽  
Pure Gold ◽  
Metal Artifacts ◽  
The Third ◽  
Early Dynastic ◽  
Gold Silver ◽  
Third Millennium ◽  
Third Millennium Bc ◽  
Placer Deposits ◽  
The Many

Abstract The many gold and silver artifacts from the Early Dynastic Royal Tombs of Ur in Mesopotamia are among the greatest metal finds of Ancient Mesopotamia in the third millennium BC. Within the framework of a research project, 32 of these artifacts were analyzed for their composition using a portable X-ray fluorescence spectrometer and a scanning electron microscope. Predominantly gold-silver alloys rather than pure gold were identified, containing up to 50 wt.% of silver and often with additional copper content well above 10 wt.%. This spectrum of composition ranges from alloys that could be of natural origin to alloys that were intentionally produced. Some gold artifacts were deliberately blended to gold-silver-copper alloys for color gradation. In addition, Sumerian written sources from the end of the third millennium BC can be compared to the results of the analyses of this study and offer more information on the processing of these metals at that time. In the present study, it is shown that gold originating from placer deposits was brought to Ur. Direct association of gold artifacts with lapis lazuli in many precious objects from the Royal Tombs and the particular composition of inclusions of platinum group minerals in the worked gold both point to a possible provenance in northern Afghanistan. One significant result was the confirmation of the use of depletion gilding for the removal of copper from surfaces; the technique of refining silver-bearing gold, known as parting, is not thought to have been known at this time.A previous version of this paper has been presented as a talk at the 62e Rencontre Assyriologique Internationale of Philadelphia 11th–15th July 2016 by A. Hauptmann, S. Klein and R. Zettler under the title: “A. Hauptmann, S. Klein, and R. Zettler, Sorts of Gold, Sorts of Silver from the Royal Tombs of Ur, Mesopotamia”. “For the late Hans-Gert Bachmann, the pioneer of ancient gold metallurgy. (Andreas Hauptmann)”

X-ray computed microtomography for the structural analysis of jewelry from the Museum “Royal Tombs of Sipán”

2020 ◽  
Vol 35 (S1) ◽  
pp. S38-S42
Author(s):  
Soraia Rodrigues de Azeredo ◽  
Roberto Cesareo ◽  
Angel Guillermo Bustamante Dominguez ◽  
Ricardo Tadeu Lopes
Keyword(s):  
Structural Analysis ◽  
High Resolution ◽  
Copper Alloys ◽  
North Coast ◽  
Flat Panel ◽  
X Ray ◽  
The North ◽  
Gold Silver ◽  
Computed Microtomography ◽  
X Ray Computed

Precious ornaments from the Museum Royal Tombs of Sipán were analyzed by X-ray computed microtomography (microCT). The ornaments analyzed were golden earrings produced by the Moche culture that flourished along the north coast of present-day Peru between approximately 100 and 600 AD. Sipán, also known as Huava Rajada, is a mochica archaeological complex in the north of Peru. In particular, the spectacular jewelry, mainly composed of gold, silver, and copper alloys, gilded copper, and tumbaga, from the Museum “Royal Tombs of Sipán,” in Lambayeque, north of Peru, are some of the most sophisticated metalworking ever produced of pre-Columbian America. A portable microCT system consisting of a high-resolution flat panel detector and a mini X-ray tube were used for the structural analysis of these ornaments. The microCT images show parts of the internal structure, highlighting the manufacturing technique and gold sheets joining techniques of the Moche artisans. Furthermore, the advantage of using the portable microCT system for nondestructive testing is clear when the sample cannot be taken to the laboratory.

scholarly journals Local Plasmonic Studies on Individual Core–Shell Gold–Silver and Pure Gold Nano-Bipyramids

2014 ◽  
Vol 118 (44) ◽  
pp. 25643-25650 ◽  
Author(s):  
Raul Arenal ◽  
Luc Henrard ◽  
Lucian Roiban ◽  
Ovidiu Ersen ◽  
Julien Burgin ◽  
...  
Keyword(s):  
Pure Gold ◽  
Core Shell ◽  
Gold Silver ◽  
Individual Core

scholarly journals More than redox, biological organic ligands control iron isotope fractionation in the riparian wetland

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elaheh Lotfi-Kalahroodi ◽  
Anne-Catherine Pierson-Wickmann ◽  
Olivier Rouxel ◽  
Rémi Marsac ◽  
Martine Bouhnik-Le Coz ◽  
...  
Keyword(s):  
Redox Reactions ◽  
Isotope Fractionation ◽  
Isotopic Fractionation ◽  
Isotopic Signature ◽  
Organic Ligands ◽  
Riparian Wetland ◽  
Fe Isotopes ◽  
Preferential Binding ◽  
Isotope Systematics

AbstractAlthough redox reactions are recognized to fractionate iron (Fe) isotopes, the dominant mechanisms controlling the Fe isotope fractionation and notably the role of organic matter (OM) are still debated. Here, we demonstrate how binding to organic ligands governs Fe isotope fractionation beyond that arising from redox reactions. The reductive biodissolution of soil Fe(III) enriched the solution in light Fe isotopes, whereas, with the extended reduction, the preferential binding of heavy Fe isotopes to large biological organic ligands enriched the solution in heavy Fe isotopes. Under oxic conditions, the aggregation/sedimentation of Fe(III) nano-oxides with OM resulted in an initial enrichment of the solution in light Fe isotopes. However, heavy Fe isotopes progressively dominate the solution composition in response to their binding with large biologically-derived organic ligands. Confronted with field data, these results demonstrate that Fe isotope systematics in wetlands are controlled by the OM flux, masking Fe isotope fractionation arising from redox reactions. This work sheds light on an overseen aspect of Fe isotopic fractionation and calls for a reevaluation of the parameters controlling the Fe isotopes fractionation to clarify the interpretation of the Fe isotopic signature.

Age and Composition of Zircons From the Devonian Petrivske Kimberlite Pipe of the Azov Domain, the Ukrainian Shield

2021 ◽  
Vol 43 (4) ◽  
pp. 50-55
Author(s):  
L.V. SHUMLYANSKYY ◽  
V. KAMENETSKY ◽  
B.V. BORODYNYA
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Continental Crust ◽  
Kimberlite Pipe ◽  
Zircon Crystal ◽  
Precambrian Rock ◽  
Weighted Mean ◽  
Terrigenous Rocks ◽  
Devonian Age ◽  
Isotope Systematics

Results of a study of U-Pb and Hf isotope systematics and trace element concentrations in five zircon crystals separated from the Devonian Petrivske kimberlite are reported in the paper. Four zircons have yielded Paleoproterozoic and Archean ages, while one zircon grain gave a Devonian age of 383.6±4.4 Ma (weighted mean 206Pb/238U age). The Precambrian zircons have been derived from terrigenous rocks of the Mykolaivka Suite that is cut by kimberlite, or directly from the Precambrian rock complexes that constitute continental crust in the East Azov. The Devonian zircon crystal has the U-Pb age that corresponds to the age of kimberlite emplacement. It is 14 m.y. younger than zircon megacrysts found in the Novolaspa kimberlite pipe in the same area. In addition, Petrivske zircon is richer in trace elements than its counterparts from the Novolaspa pipe. Petrivske and Novolaspa zircons crystallized from two different proto-kimberlite melts, whereas the process of kimberlite formation was very complex and possibly included several episodes of formation of proto-kimberlite melts, separated by extended (over 10 M.y.) periods of time.

scholarly journals Trace-element and Nd-isotope systematics in detrital apatite of the Po river catchment: Implications for provenance discrimination and the lag-time approach to detrital thermochronology

Lithos ◽  
2017 ◽  
Vol 290-291 ◽  
pp. 48-59 ◽  
Author(s):  
Marco G. Malusà ◽  
Jiangang Wang ◽  
Eduardo Garzanti ◽  
Zhi-Chao Liu ◽  
Igor M. Villa ◽  
...  
Keyword(s):  
Trace Element ◽  
Lag Time ◽  
Po River ◽  
Nd Isotope ◽  
River Catchment ◽  
Isotope Systematics

scholarly journals I. The liquation of gold and platinum alloys

1890 ◽  
Vol 47 (286-291) ◽  
pp. 180-186 ◽  
Keyword(s):  
Copper Alloys ◽  
Gold Alloys ◽  
Silver Alloys ◽  
Platinum Alloys ◽  
Silver Copper ◽  
Gold Silver ◽  
Almost All

It is a well known fact that when molten alloys of certain metals are cooled, some of the constituents separate and become concentrated either in the centre or in the external portions of the solidified mass; to this segregation the name of liquation is given. It is specially noticeable in the case of silver-copper alloys, and its importance is now being widely recognised in almost all branches of metallurgy. In the case of gold, however, the phenomenon of liquation does not appear to have been much observed. Gold alloys, to the value of many millions sterling, pass annually from hand to hand upon the results of assays cut from the external portions of ingots, which assays cannot, of course, be trustworthy, if the centre of the bars differs in composition from the external portions. Peligot has recently endeavoured to obtain evidence of liquation in gold-copper alloys, and has concluded that it does not exist. Roberts-Austen, who has devoted much time to the study of liquation, has also satisfied himself that gold-silver alloys do not rearrange themselves on cooling.

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