Update to previous post:
Gerard emailed me a very informative reply. I won't attach the pictures for the book (because of copyright, I think), but here's a picture of Gerard's beautiful vases.
Here's part of what Gerard wrote: In 1997 there was in The Hague, The Netherlands an exibition of old and modern Murano glass.
With the exibition there was also a beautiful book written by Rosa Barovier Mentasti and Adriano Berengo (img 1).
At page 50 there are two picture of objects by Archimede Seguso (img 2).
By the green vase it's the way of the amber layer and you can't see an extra colourless layer like a lot of simmular vases of other makers/designers.
The vases of this type of Archimede Seguso are very heavy; more than vases of other designers/makers.
I have two vases from this serie from 1955 (last picture)
Here's part of what I wrote back:
Your two pieces are very lovely and I'm sure they're Seguso. I compared the two with the similar vase I have and mine is less finely made, and there is a lot of clear glass added at the end. I'm pretty sure now that my piece was made by a lesser furnace imitating Seguso. Sue's piece I'm still not too sure about. I think one would need to see the actual vase to know.
I suppose I always tend to be a little careful in attributing a particular type of vase to a well known maker as the the attribution then becomes even wider.