An iffy Ostia follis

[Per D]

Hi,

I'm terrible at spotting fakes, so any thoughts on this Maxentius follis (should be RIC 16) would be appreciated.

The coin is light, only 4,42 gm (average for this issue is something like 6,25 gm), and has a peculiar graphite-colored patina (there is red copper underneath, though). What makes me really suspicious is the surface, but I can't tell whether the uneveness, exaggerated in the picture, is the result of casting or corrosion.

Per D

[Victor]

from the picture, I would not think it is fake. The surfaces just seem rough from corrosion, which might also account for it being underweight. Also the edges are ragged, like it has lost some material, also contributing to it being underweight. Plus, you can find underweight and overweight folles sometimes, as they only had to strike a certain number per pound, I think 48 to the pound for this issue. Though the weights are usually very close, they can vary.

[Per D]

Thanks , Victor, for a very quick response!

I guess an acidic environment could have caused both the corossion and a kind of surface enhancement giving the coin its silvery appearance.  Anyway, I'm glad it's not an obvious fake as I rather like it.

[Victor]

I guess an acidic environment could have caused both the corossion and a kind of surface enhancement giving the coin its silvery appearance.

Yes, corrosion can definitely give a coin a silvery appearance. Here is a link to an article that explains the chemistry behind this...the pertinent info is at the end of the article.

Metallurgy and Metallography in Numismatics

[Per D]

Belated thanks for the linked article. It was an interesting read.
/Per D