If this coin is Greek, the 'C' is actually a sigma. If so, there is only one possibility for this coin, the mysterious island of Astypalaia.
Nothing seems to be known of this island in ancient times. Wikipedia helpfully says “The island had no particular importance during the ancient age.” The current population is 1238 residents, I imagine the ancient population would have been about the same. It's not a small island, either, 99 square Km.
Numismatically, the odd thing about this island is that it copied the types of Seriphos, the home of Perseus. No one knows why. All of the Perseus coins from the island that I've seen use the regular '&Sigma' sigma, so this coin is an oddity if I've identified it correctly.
Müller incorrectly attributed Alexander III staters and tetradrachms with harpa control mark to Astypalaea. Price cites Noe assigning the tetradrachms to Argos and cites Newell assigning the staters to Salamis. BCD seems to suggest the A/harpa bronzes belong to Argos, leaving Astypalaea with very few types.
There is a museum on the island with ancient coins. Perhaps one day I'll be able to visit. I'm very curious to know if they have any of their early gorgon and Perseus bronzes.
If anyone can suggest another attribution for this coin I'd be very interested.