hi,
I was not disbelieving anyone, just asking for confirmation that they were one and the same company! as I had now found photo of it. Looks like the
Mandruzzato glass is very similar just having trouble tracing colors.
No worry. I was not concerned. The last column of the product page has the colors, but they are difficult to see. I had a brown Mandruzzato vase that had a similar yellow-amber layer. I've posted a picture of it. My only hesitation in calling your glass Mandruzzato is that art glass people often copy each other. Unless a style is really distinctive, it is always good to look at the possibilities -- glad to see you are doing it. It would be nice if you found it is something really expensive. Mandruzzato pieces are pretty, but produced in good quantities, so don't have a high value (as you can see from the site). They are made so the common person can afford pretty glass.
If you have a black light, you can check to see if the yellow layer glows. Some of the vases discussed on the Murano board were uranium glass.