I may have this wrong, but I'm sure I have seen that pattern and style sold in cased glass and I'm sure I thought it was id'd Empoli or Opalina Fiorentina. However when I saw a cased one I didn't buy it as I wasn't particulary sure the thickness of the glass or the casing was right (the cased one that is). And just to add to this, I have a huge neodymium vase that is in the snowflake pattern that is also seen in cased glass and id'd as Empoli or rather Opalina Fiorentina I believe. I ended up thinking my neodymium vase may have been by Stelvia possibly I believe? So I think your vase is Italian and an Empoli maker possibly or Stelvia perhaps.
And to add a further note, I recently did buy a snowflake vase in cased glass like my neodymium one and the thickness of the glass on that isn't particularly as thick as I thought it would be either.
So, my thoughts are they are all Italian although I was a little surprised that the thickness of the cased glass wasn't as good as I had thought it may be. If that makes sense?
m