Some lettering look like greek, but size and form remind of hungrian 17th century. I woud appreciate your help. Thanks! Diameter 15mm weight: 0.62gr
Could it be medieval Armenian? Medieval Armenian coins seem to be reasonably common, and Armenian uses its own weird and wonderful alphabet, which is distinct from both Greek and Roman (and Cyrillic).
Hmm. Toughie. You've got me there. Does look vaguely familiar (-ish), though. I can see why your mind would go to 17th century Hungarian denars. Re. Parthicus' Armenian theory, it sounds as good as anything I'd be able to guess, but I of course do not know. Might have to squint at this one and scratch my head a little more later. I do sometimes enjoy these little numismatic enigmas.
Could it be serbian 14th century? Letters may be in old slovene, then mainly used in written documents and coins?
Design looks like a denar of Sigismund from Hungary - I can't quite make out the legend though. Style doesn't look too far off on the lettering (gothic style)
I am almost sure it is Hungarian. I looked at it closely and the shield must be hungarian. The other side is probably twin cross. @FitzNigel , I think you are if not right, than very close. Thanks!