Johnphilip was right about not all lamps being drilled for the flex, as I remember seeing some just like that (I have to say, though, that such pieces don't look very elegant, imho) Also, I think I was a little off in suggesting a candle holder, as I the scale is wrong. One way to see if it were possibly a lamp base is to check whether the opening is the standard size opening required for a fitting, not that I know what that is.
However, we may be focussing too much on function rather than form. Glass light bases were made all over and establishing whether or not it is a lamp base doesn't help too much in identifying the origin of the piece. I did another quick look at similar pieces I have (photo attached), and the ones I think might be Murano have bubbles are are sommerso. The ribbed one in the picture has 18 ribs, despite being much smaller than your piece, so ribs don't rule out Murano. The ribbed lighter base I have (same basic shape, but with an additional base polished on the side, and which has Murano label) has a lattimo core covered in gold foil and then cased in clear. I guess what I'm suggesting is that the shape could well be Murano, but I'm now less certain about the colour. Sorry for being so tentative. I hope for you, like me, the fun is partly in trying to figure things out.