Authenticity testing via Radiogenic isotopes?

[JarretGax]

Hello again everyone,

   So i was doing some 'heavy' reading into lead(Pb) and its properties and came across this passage:

Lead consists of four stable isotopes: 204Pb, 206Pb, 207Pb, and 208Pb. Local variations in uranium/thorium/lead content cause a wide location-specific variation of isotopic ratios for lead from different localities. Lead emitted to the atmosphere by industrial processes has an isotopic composition different from lead in minerals. Combustion of gasoline with tetraethyllead additive led to formation of ubiquitous micrometer-sized lead-rich particulates in car exhaust smoke; especially in urban areas the man-made lead particles are much more common than natural ones. The differences in isotopic content in particles found in objects can be used for approximate geolocation of the object's origin.

Shamelessly pulled from the wiki. Here is the link to entire article I was reading: https://wikivisually.com/wiki/Isotopic_signature

My thoughts since lead is a common impurity in many Roman coins could we not use this method to rule out some coins as fakes because they contain lead sourced from say China or South America?  I have read that we can source some coins to the mines in Spain or from the Balkans.  Would any other elements commonly found in ancient coins also help to locate the materials native location?

Im not sure if the proposed testing would be able to produce results without damaging the coin in question.

I would be interested in anyone's thoughts on the matter.  Ive been working my way through the Fake Coin Discussions and authenticity has been on my mind.

[Din X]

What could possibly be done is a lead isotope analysis or alloy analysis.
Some elements have isotopes (different number of neutrons) and the number of neutrons is different on different locations.

Sometimes it is possible with this to locate the origine (location) where the ore was found.

Google archaeometry !!!!

There you will find how they try with modern science to authenticate ancient objects.

[JarretGax]

I stumbled across this old post that answers some of my questions proposed above: https://www.forumancientcoins.com/board/index.php?topic=48616.0

Thanks Din X ill check that out, thanks!

[John S3]

Great links.  I went to MSU website about this http://archaeometry.missouri.edu/services.html#nonarchaeo.  In my work we had a project related to parts quality management.  One of the engineers at one of the centers tested my wedding ring to show me some of their processes in one of the what to my non-technical understanding was a mass spectrometry device.  It didn't damage my ring at all and was super fast.  What was interesting was the the other "spikes" indicating other element content/ratios.  I wonder if just these simple tests with a proper baseline for every issuance wouldn't indicate obvious fakes because of their deviation in these other trace elements?  I assume the issue is that minting runs did not use fairly uniform source materials- melting down war booty or whatever as they went?

[djmacdo]

One problem with this approach is that the Roman silver coins from the mid-first century on were surface enriched, so that analysis of the surface grossly overestimates the silver content.  Another problem is that often Roman alloys were not perfectly uniform and analyses of different places on the surface of a silver coin will sometimes produce much different results.

[Hydatius]

For silver and bronze the gold standard is wet analysis, but the coin is destroyed (hence the arguments of destructive vs non-destructive analyses). The surface of a bronze or silver is simply too oxydized and contaminated to be of any real value. See the video and especially the graph at 00:55 comparing the accuracy of the various methods. https://www.youtube.com/watch?v=wQS_2PaoEL4
Richard

[Joss]

Some forgers buy very worn coins and melt the silver to mint their fakes...

[John S3]

@djmacdo Right, but with MassSpec you would get the concentrations and variance in type even for the surface metals.  Test enough of verified authentic coins (baseline) maybe unique to the mint for specific years would yield indicators like 5-8% Zn, 10-14% Cu, .05-1% Ga for RIC X, and secondary indicators could be trace elements. @Joss- clever re-minting would defeat this true.  Like I said maybe melting booty makes baseline unattainable but for mine to mint situations anyway?