I would agree with the finger bowl decision. These things have been made for over 200 years, and they are found occasionally with backstamps by most of the big factories, which suggests those are C20 - although oddly they don't seem to 'travel' as much as other types of table glass - personally I've yet to find a non-English example - although obviously they are out there, as I've seen them on advertised on ebay, often.
Sometimes they are seen with a snapped pontil scar, suggesting probably pre 1800 - but most of the C19 examples will have a polished pontil depression like this one. Without a backstamp, attribution is virtually impossible, and they might have been made anywhere.
They come in ruby, cranberry, green, uranium, turquoise, pale amethyst, deep amethyest - cut, pressed, mould blown and every form of decoration you can imagine.
They make a good collecting theme, and don't take up too much space - I found a custard cup this morning that matched the machine acid etched pattern on one of my finger bowls, but not a clue as to who made them