I have been trying to navigate the mine field that is bubble base cylinder vases.
I thought I had cracked it when I saw the photo on page 10 of Fire & Sea....... The coloured portion appears to have a very distinctive tear shape at the bottom.
However, Robbo's vase on this thread appears to have a flatter base to the colour, although this could be the angle of the photo.
Found this one online which appears to be signed similarly to Robbo's
https://www.etsy.com/sg-en/listing/670038464/iittala-finland-tapio-wirkkala-bubbleAnd that one also appears fairly flat at the bottom of the colour.
So now I'm wondering whether this can vary across pieces from the same maker?
The one possible point of differentiation that may prove more helpful, is the base. The Iittala ones appear to have a bigger hole than any of the other examples I've found, and I have had pieces in the past which I believed to be Polish, and which looked drilled out and very rough.
Also, the Iittala appear to have a flatter foot rim in the photographs, and it would be helpful if somebody with a confirmed piece could post a photo with their piece angled to show this aspect of the base.
I have a golden Amber one which I will add to this thread once I can get back into the glassgallery to upload some photographs, I suspect it will be a match for Anne's Retailed by M&S.
Finally, I wonder if weight might be useful to help differentiate between them, so just to get the ball rolling mine weighs 575g.
Cat