I would suggest that the dimensions discount this being a finger bowl - they're usually noticeably bigger, and my opinion would be that it's not a salt either, based on shape and what appears to be an iridescence inside and out. Salt tends to damage surface coatings, which is why, usually, salts are simply a solid coloured glass, and although they are known to occur in many colours, traditionally they have been either clear or blue.
Might this possibly be a pin dish or similar? It is attractive with that hammered carnival look - hopefully someone with recognize that surface decoration.
