Silver Plated Septimius Severus Denarius

[RL]

I acquired this Septimius Severus denarius as 'collateral damage' along with a group of low-value bronzes (all of which I am confident are genuine).

The auction house (which I consider reputable, so I suspect this simply slipped through the cracks when it was listing a large number of low-value coins) described it as a denarius without any qualification. There are however several obvious issues, the main one being that the coin appears not to be solid silver but rather to have a light wash of silver over bronze. The detail is also rather soft and perhaps that points to it being cast although in hand I am not confident that any of the other surface anomalies visible (eg possible 'pearls' under the horse on the reverse) indicate casting as opposed to corrosion of the underlying bronze. On top of that it appears to be quite harshly cleaned (that is, both the silver and bronze are very bright).

I am not holding out hope of it being genuine, but am curious as to whether anyone has an opinion as to whether it is a modern or (overcleaned) ancient fake? While I have handled some ancient fouree I don't feel confident to judge, particularly given the apparent overcleaning.

There don't seem to be any matches in the fake coin reports.

I attach both the vendor's image and some lower quality ones of my own, as the vendor's image shows better detail on the coin but doesn't catch the contrasting colours as well as my humble iPhone.

I believe it is meant to be an imitation of RIC IV 74

3.01 g / 16 mm

edited for spelling/grammer

[SRukke]

I think ancient. It could be a fouree but looks more like poor grade silver with copper leeching through. I have a tet that looks similar.

[RL]

Thanks SRukke

Leaching of copper through poor grade silver is not a process I have heard about before. I would be curious to see other examples. I have had a look through your gallery and am guessing you are referring to this Hadrian Tet? https://www.forumancientcoins.com/gallery/displayimage.php?album=lastup&cat=-2434&pos=691

(n.b. great gallery by the way, I have been looking at a lot of Postumus coins lately so found your collection rather distracting!)

[SRukke]

Thanks SRukke

Leaching of copper through poor grade silver is not a process I have heard about before. I would be curious to see other examples. I have had a look through your gallery and am guessing you are referring to this Hadrian Tet? https://www.forumancientcoins.com/gallery/displayimage.php?album=lastup&cat=-2434&pos=691

(n.b. great gallery by the way, I have been looking at a lot of Postumus coins lately so found your collection rather distracting!)

Yes, that is what I was referring to.

[peterpil19]

Hi Robert,

Here is an example of a billon tetradrachm I own. Not quite the same as yours but one where visually the underlying copper is taking over the silver!

According to wikipedia the denarius was steadily debased over time under the Severan emperors so that during the reign of Septimius Severus there would have been a significant propotion of copper: https://en.wikipedia.org/wiki/Denarius

Peter

[PeterD]

Under Septimius Severus the fineness of the coinage went from about 80% to 55%. The rest was base metal, mainly copper. After striking, the coins were 'pickled' to clean them. This had the effect of dissolving the oxidised copper on the surface and leaving behind a bright silver surface. This is known as silver enhancement, although it should more properly be called copper-depletion.

For this particular coin, I would guess that part of the outer silver layer has corroded in the ground leaving behind the silver-copper mix that constitutes the bulk of the coin.

[Matthieu P]

This denarius looks fine to me, and I don't think it's an imitation.
It's appearance and particularly the copper color is because it has been cleaned with some acid or by electrolysis.
I obtained the same result from a Caracalla denarius which was heavily encrusted: on some parts of the coin, the surface turned red, but it was not a fouree.

[RL]

Thank you for your comments everyone. It is quite fascinating. I wasn’t aware of the processes that with Matthieu and PeterD have suggested either.

[SRukke]

Thank you for your comments everyone. It is quite fascinating. I wasn’t aware of the processes that with Matthieu and PeterD have suggested either.

Whatever you do, do not use electrolysis. You will quickly ruin a coin. Electrolysis doesn't just take the patina off, it takes part of the metal also.