Well if said jeweler or scholar or whatever was blatantly overt about their faith, then the cleric should act appropriately.
In the Berylite case, the cleric may hold his tongue or indicate distaste or whatever seems appropriate at the time and in keeping with what Toran thinks about Beryl.
In the Corathite case....well, Toranites pretty much view Corath worship as an illegal act, so again, the cleric should act appropriately.
That said, if the relationship is not known, then there's no reason to act any differently.
Also, remember that Clerics have that wonderful cantrip Divine Relation. It doesn't tell specific deities, but it does tell the relationship between the cleric's deity and the target's.
A handy tool...people should use it.
