Postumus question

Seller describes it as unlisted. I found only one example in RIC in dated Ants, RIC 54. Seller describes it as bronze, all other listings I have found are for AR or billon.

Sellers info:
Unrecorded Bronze Antoninianus with Good Detail, Maximum Diameter 24.2mm, Weight 3.04g, Die Axis 0o;
Obverse - IMP C POSTVMVS P F AVG, Radiate Draped and Cuirassed, bust right;
Reverse - PM TRP COS II PP, Emperor standing left in Military Dress, holding Globe and Spear.


I found a very close match on vcoins:
https://www.vcoins.com/en/stores/fo...us_cologne_260_ad_vf_nice/675490/Default.aspx

Yeah, it's got green bits on. No idea what I am going to do with it when I get it. Could it be silver under all that crud? Anyone got an opinion?

 

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i don't know pish, i would guess yours was just a lower grade billon than the one on forum

 

Pish this is the closest I have to yours.
Postumus but different reverses.
One was listed a bronze the other a Billon, but after some digging around I found them both to be Billon.
Hopes this helps some.

 

I suppose it could be anything under that crud.

 

Neat coins @Smojo.

 

We've seen your magic. I bet you can get the crud off of there.

 

I would have to have a long hard think about it, once it was in hand. Those shadows I suspect is more green stuff under the brown. I might try removing just a spot of green to see how it affects the brown stuff.

 

They look like hard deposits. I'd really like to see it when you're done with it.
I've not been doing anciets very long but from what I've seen the hard stuff seems to form around breaks.
Of course I can be wrong I've not seen much in my short time.

 

I know my method can get rid of the green stuff, I doubt that it will have much effect on the brown. It is reasonably attractive (to me) as it is. If I do try anything, I will certainly post, good or bad.

 

RIC 54 is correct, it's not unlisted. Postumus set out to coin ants of fairly high fineness, but by the time he inaugurated the Gallic Empire, Eastern ants had become quite debased. So trading Western ants for Eastern would have been swapping good money for bad. This forced the alloy in Postumus' ants to become quite debased in a short time. That's why you get coins that look to be almost pure bronze, like yours, and others that have much "better" metal, like the one I sold in my last auction..



Postumus, AD 260-269
Billon antoninianus, Colonia Agrippinensis (Cologne, Germany) mint, AD 260.
Obv.: IMP C POSTVMVS P F AVG; Radiate, draped and cuirassed bust right.
Rev.: P M TR P COS II P P, Postumus standing slightly left, wearing helmet and military attire, globe in right hand, spear vertical in left hand.
Reference: RIC Vb 54 (Lugdunum), p. 341

 

Thanks JA, that was very useful. I was puzzled that I hadn't seen another one described as bronze.

 

I'm going to guess that Postumus' ants should properly be called billion - even the least fine probably have some silver in them. After that, I'd say bronze - I don't know of any studies, but I'm willing to venture that the ants of Tetricus and Victorinus, for example, are wholly base.

 

I've noticed that billion coins age differently than silver or bronze. For one thing, they often don't acquire the hard patinas you find on bronze - the small presence of silver somehow prevents that. They do acquire mineral deposits, like the OP coin, and many of them tone to the color of milk-chocolate, also like the OP coin.

The kind of toning you find on Dave's second coin may be due to an uneven alloy mix, which is also very interesting. Somebody didn't stir the pot well enough before it was poured. Billon of higher fineness, like the coin I posted, seems to behave similarly to good silver.

 

Here's a nice milk-chocolate of Gallienus...

 

Again, very interesting. I haven't been collecting long enough to see these effects. One of my husband's friends is a metallurgist, I think I am going to have to collar him when he next visits.

 

Now that is a really pretty reverse. I see what you mean about the colour.

 

I'll doubt that you will find anything under the brown that you want to see but the type is an early emission which makes silver expected. I would like to know what your method is that would take off the green and not the brown if there is silver below. If you remove the green and like the brown, I would leave well enough alone. Otherwise it is time to get out the lemon juice or vinegar and see if you can ruin the coin.


While I agree with JA's comment on rapid debasement, There are an awful lot of coins with later emission dates than this with what strikes me as better silver. I suspect there is more to this than a straight early to late debasement but I do not have the answer. Below is a Mars with TRP IIII (later than yours by two years assuming normal use of the numbers). It still has a bit of a silver/billon look. I'd probably risk cleaning it but I'd probably be a bad person to advise on anything related to cleaning.

Maybe 'properly' billon but some are pretty good looking silver color. 15%? More? IDK!

 

Well you know @John Anthony one of those two I got from you.

 

I can recall seeing very few coins of Postumus that struck me as silvered in the sense we see in later coins. By this I mean the wash that wears away revealing copper below. Can anyone provide a photo of a definitely silver washed Postumus as opposed to a low grade, poorly mixed billon? Late ones in my collection just look brown. The same question can be asked of later Gallic emperors. When did wash start as a practice both in mainstream and separatist states?

 

I can't show you one - I've noticed the same thing. Silvering seems to have been a technology practiced by the Eastern mints only.