Hello! I'm not very experienced with Roman coins but I recently came across an interesting one. I thought originally it was a silver Severus coin just a normal type with some kind of stuff on it. But as I got closer to the actual coin I realised it was copper or some base metal and it had come from inside. Anyway check the photos and see what you think. Maybe the foil silver over copper method? Is this unusual for this coin? Thanks! That bit in the second photopwith the flap and coppery stuff is where it I guess burst out? Thx
Yes not the best in using my phone as I'm not with my camera. Here's a magnified one: The coin half way through cleaning:
I missed this before. If that coin in liquid is the same one as the Septimius that started the thread, there is no way it is a foil fourree. The abuse you put it through would have broken through at the same time it was removing all those deposits. Below is a Julia Domna foil type fourree from roughly the same time.
Try the bleach test pour bleach over the coin.. it takes seconds( less than 30) for the bleach to react to it( if its really silver) it will turn grayish- and even dark gray. Unlike most metals,silver is very reactive in that regard. its the cheapest and its fairly effective-( not guaranteed though) Magnetic slide test doesnt work then theres silver testing kits Nitric acid apparently is said to be the only surefire way to prove its silver- and not just silver- but solid silver and not plated
The copper deposits on the surface don't necessarily indicate that it is a fourree, particularly (as Doug notes) as the deposits appear to be over the silver rather than under it. There are a couple of other possibilities - it may have been hoarded with copper coins (see Doug's article here https://www.forumancientcoins.com/dougsmith/grade3.html - scroll down to the second to last coin on the page). Alternatively, the copper might have leached from inside the coin itself - Septimius Severus debased the silver content of his coinage quite severely during the course of his reign. A lot of his denari are a high % base metal (usually copper). I understand that after minting they were treated at the mint with acid so that the copper on the outer layer of the coin was depleted making the coins appear pure silver but over time the residual copper in the core can "leach" through to the outer layer. If you want to get all academic about it have a read of these: https://www.academia.edu/362473/H._..._Roman_and_Eastern_Issues_Galux_16_Milan_2003 http://ijcs.uaic.ro/pub/IJCS-12-15-AlZahrani.pdf NB there is a similar example on a Dominion coin here (Ctrl F: CAESAR AVG F DOMITIANVS will take you to the right coin) http://esty.ancients.info/imit/isitfourree.html
Yes I've got all the testing stuff the silver test was indicating very low amounts of silver in a yellowish result I'll have to do a magnified look at a test I guess. The copper was all over it and I used oxyilic acid as I heard it doesn't effect solid silver metal and for some reason a citric acid cleaner as one acid on its own seemed to stop working after a while so I had to swap every so often. And verdegris goes redish in acid I've found although this coin looks like it's desolved back to the purerer copper now. When I was testing with the really strong acids for the Nobel metals I did get green from the 'red' (coppery) deposits as such also which is usually a copper trait I think. Anyway: Great thanks that was what I was after I wasn't sure about leeching. But it does look like a flap I just don't want to lift it yet I guess. I'll do a specific gravity test next not sure if it will enlighten but worth a try... And I'll go over that info. properly... It's all about learning anyway . Thanks all.
https://babel.hathitrust.org/cgi/pt?id=inu.30000104992965;view=1up;seq=7 Before abusing your poor coin any more, read the standard reference of plated coins which has now been placed free online at the above address. I paid $50 for my copy and paper books are still available or those who do not like to read online. I consider it a great book. You can run all the tests you want on the coin but the only one that will reveal the interior is to cut it in half as Campbell shows in the book (great photos). Specific gravity will not tell you what a coin has inside but only an average of the alloy metals, corrosion and air pockets. Splashing acid on the surface and a notch as shown by Pawn Stars is a test to reveal base metal under relatively pure silver if you don't mind cutting that notch but will not tell much if the surface alloy is largely copper as well. The coin is not a high dollar item but IMO too nice to cut in half to show what is pretty obvious. Fourrees of various styles tend to degrade in predictable patterns of wear and corrosion. The Campbell book shows a number of styles. By the time of Septimius Severus, there was little enough silver in a real coin that it was not profitable to make the best fourree styles like foil and most countrfeits had very thin silver coatings that are very delicate and rarely survive even normal handling. High grade examples usually have bare patches showing copper and many are completely without remaining silver. Examination under a stereo microscope will make it clear which metal was on top.
Please don't use this methods for testing silver these will destroy the coin I suggest go to a jewelry that has XRF machine and they can test without any affect on the coin.
Great interesting stuff lots to learn about. And yes I don't want to try the bleach test and I have the acid etc tests anyway. I know somone with that x ray device. I may get one one day but for now it's too much for me. The coin is now in a rehibilitation clinic and is slowely recovering.
Ah and I missed this for some reason... So I was going between the weak citric acid cleaner and oxyilic acid which don't attack copper or silver metals only the oxidised copper. What would the problems / abuse be? And I guess no the acids wouldn't eat through a hole with the pure copper as they won't react with it? Are you talking other metals or something else? Thanks.
