PVC Damage To A Silver Antiochus Tetradrachm ?

Beautiful coin. I'm not seeing any damage - not that I would know how to treat it, anyway.

Seems to be a very rare issue - Antiochus II Theos, possibly Lampsacus mint. The only other example I've seen is listed as an unpublished "variant of SC 486.2a and WSM 1539."

to the community

I don't see any PVC damage to this coin. It has a very nice even tone. I wouldn't do anything to it. Though if you do acetone will not hurt it.

I beautiful coin.

Having a small speck of green, which is only a color you get from a copper compound, does not at all hurt the integrity of the coin as ancient ores were not pure enough to produce a 100% silver that will not have other metals as trace impurities. So if the coin was perfect for silver content you would have a problem. Either way, as most of the coin is a fine silver it is not like the green area will grow as it is based on the copper impurity natural to the composition from the ancient mint. I think collectors understand this when they see the coin in my opinion.

That's a pretty coin. A speck won't hurt your coin niki just leave it alone. Hope you stay around.

There are multiple non-destructive chemical analyses that could be performed if you have access to specialized laboratory equipment. For example, with a scanning electron microscope (SEM) and energy dispersive spectroscopy, you could look at the elements in the green blob and potentially determine the constituent elements. For finding carbon, you would more likely need a different piece of equipment on the SEM (wavelength dispersive spectroscopy).

Have you considered simply giving this coin an acetone bath?

To my regret, I have no access to such equipment. I have not decided yet to wash the coin in acetone! I just want to keep it in the right way in the future.I find ,it difficult to decide what is right to do in this case. :)

As others have said, this is a beautiful coin. However, I do see a bit of discoloration in the obverse left field and the hair (left of the headband) and ear. I cannot tell if this is a true discoloration or the result of the lighting which is stronger on the right side of the obverse. If the tone of the obverse is uniform, then I would leave it alone. However, if there is a residue on the obverse left, then a very light "scrub" of the affected area with a que-tip soaked in acetone might be tested. Only test a small patch at first, and check the que-tip to see what it is picking up. Light circular strokes with almost no pressure; let the acetone do the work. If it changes the tone, then extend the "scrub" to the rest of the affected area. If nothing happens, I would leave it alone.