Hi Della - well it's more or less certain to be European and Not Classic American. I wish I could give you the absolute definitive answer as to who made it - but I can't. I have seen the vase before, but I have not been able to positively attribute it. Everytime I think I'm ready to press the "eureka button" I find there are details not matching.
Hopefully someone will ID it for us (please, pretty please someone).
One rule of thumb (not always an indicator, but it can help along the way) is that the base (underneath) of Classic American carnival is usually not ground. The base of a lot of European is ground (not always, but often).
What's the base of your piece like? Does it have the mirror shiny grind of your Inwald piece?