Here is a good paper reflecting your thoughts on a research project done to try to simulate ancient silvering - attached below. There are dozens of articles in ancient & modern (i.e., post 1500) periods explaining mercuric silvering. Normally at the end the planchets are annealed to drive off the mercury due to its low boiling point but almost always trace mercury (i.e., <5%) is usually left behind and detected as a stable mercuric silvered compound and non-hazardous in this inert state. Unfortunately to send this one out it would cost around $400. I know someone with a cheap XRF gun for FREE but for what purpose? I already know they are silvered - I know the NGC label is WRONG where it states AU - cleaned. Lighter elements based on atomic weights usually below Magnesium (from memory) need a vacuum chamber for accurate quantitative values but an XRF gun nevertheless would indicate silver IMO IF detected at values greater than 1%. Obviously I might do the later - see my other paper in the Newman Portal on a 1821 Zacatecas 8R using a $400 analysis and showing it was not cleaned but metallurgically made with non-homogenous surfaces due to impurities in the alloy made during the critical time of Mexican independence. They did not publish it in the Mexican Numismatic Association journal since they needed a bigger sample population. I have to agree but at $400/coin - LOL.
See this ancient paper - one of my favorites for ancient silvering of coins which follows until silver plating and eventually Sheffield plating (most advanced - as per the GNL book) take over as the preferred method - as you say due to its short-term existence on the surface of the coins.
https://www.forumancientcoins.com/h...%20coins.pdf
See this ancient paper - one of my favorites for ancient silvering of coins which follows until silver plating and eventually Sheffield plating (most advanced - as per the GNL book) take over as the preferred method - as you say due to its short-term existence on the surface of the coins.
https://www.forumancientcoins.com/h...%20coins.pdf





















