I have an "unofficial imitation" (or
contemporary counterfeit) of a Metapontine
incuse stater. Not as much as the real thing (which I also have in some numbers), but I have never seen one before, besides this one. Most collectors would avoid it, but to me it is an addition to my rather specific
collection. If you have a regular issue from a regular
mint or monarch, it is probably easy to find something comparable and therefore deduce a
price. If you have something odd or strange (but otherwise a perfectly
good coin, not a problem coin), then just because it is unknown, in most collector's eyes it will be worth less, but for a specialist collector, it may be worth more, or if not worth more, at least more desirable.
There are more coins from
antiquity than one would expect for which there is only one or two known. By known I not only mean by scholars or
museum collections, but by anybody. On the other hand, you might have a coin specimen of which only one or two are known, and a huge
hoard of them get discovered tomorrow, (pseudo-Rhodian). In any case, it is not like modern coins, where we have
mint numbers, and we are pretty sure that the overwhelming majority have not been lost or buried in a
pot. It could also be that your coin was found in a large
hoard 100 years ago, and so while it is not
rare, it is
scarce with example not often appearing in the market or even in reference manuals.
Look for the answer for the
attribution of these coins, but if you don't find it, don't be discouraged, you might have some that nobody else has. Whoever else
had them might have passed them on because they
had the same problem. I think any advanced collector who has gone through
bargain bins, has a few coins that they don't know what to make of them. They consider them interesting mysteries, and you might consider these
part of yours. But, it does sound like you know what the
obverse means, which means you are not facing a
complete question mark.