Coin Degeneration?

I agree doesn't sound too good. But it could also mean that the coin is a fouree. Can you post a picture of it here?

Here is what CNG says about it....
Pescennius Niger. AD 193-194. Fourrée Denarius (18mm, 1.85 g, 12h). Antioch mint. IMP CAES C PESCEN NIGER IVST ΛV, laureate head right / ΛETER[NIT]ΛTIS ΛVG, upturned crescent with seven stars above. Cf. RIC IV 1; cf. RSC 1; cf. BMCRE, p. 71, †; cf. CNG E-196, lot 300 (all refs. for type). Good VF, find patina, traces of bronze core degeneration. Extremely rare.

So this is a contemporary fake? Rotting from the inside out?

With CNG selling or rather having sold it as Fourree it is most likely a contemporary or at least old and recognised copy.

Try it on a Christmas Pudding Coin.

Yes, if by "contemporary" you mean "ancient". Fourees are ancient fakes, made by making a "sandwich" of two pieces of silver foil folded around a base-metal core. The whole thing is then smashed together between two dies (either counterfeit dies or genuine dies "borrowed" from the mint); the silver plating is pressure-bonded onto the core, creating the illusion of a solid silver coin. It would even have tested positive for silver using the primitive chemical means available in ancient times, and you'd have needed to make a disfiguringly deep cut to punch through the silver layer and spot the fraud. Fourees are 2,000 year old ancient artefacts in their own right, and just as collectable in most cases as (and often even rarer than) genuine coins.


Correct again; this is what "core degeneration" is a euphemism for. American members will all no doubt be familiar with their modern copper-plated-zinc 1 cent coins. These modern coins are also prone to "core degradation", more commonly known as zinc rot. Because zinc is a far more chemically reactive metal than bronze and because the plating on them is much thinner, zincolns require far less time buried in the ground before "core degradation" becomes evident.

Such core degradation usually results when a microscopic hole or crack in the plating allows water to contact the base-metal core, wheich then proceeds to corrode at that spot. The corrosion products are "fluffier" than the original metal, so the corrosion spot expands, pushing the uncorroded silver plating out like a bubble.

In the case of this fouree coin, I suspect the "traces" of it mentioned are the small bumps, most visibly on the reverse below the moon after the G of AVG and inside the right horn of the moon.