Kithara On An Obol : A Mystery (At Least For Me)

0,43 gr / 8,5 mm

That looks like a pretty good match to the OP's coin @novi. Interesting that neither auction house was able to find a good reference for it.

It's not so much "no references" it's more "nobody actually knows what city it came from". With no lettering or obvious word-pun picture on it, the coin itself doesn't tell us where it came from. Which means we need archaeological evidence: "most of these were found in Ephesus, therefore the coin was most likely struck in Ephesus", that sort of thing.

With it still being classified as "unknown" in 2025, this can only mean that the archaeological evidence is either unclear or largely absent. It's entirely possible that its city of origin is an "unknown city" - a city which has been effectively erased from history, because nobody mentioned it in surviving records and the source city remains an unexcavated ruin.

If you have an NGC account and have it slabbed that would assure it's value forever. And make sure it was never lost. People hate doing that to ancients as they want to handle them, but handling such a small coin is a different story and it will be great to do if you were sending a bunch of others ones in anyway for processing.