I had a look at J Miller 2004 pp284 - grouping of three pieces
I believe the grouping is Riihimaen but not by Nanny Still (not Caithness either)
J Miller is famous for bad attributions with all it's glass, especially Riihimaen, these price guides should always be treated with the utmost caution.
The vase in question, your vase and it's brother in J Miller are not in the Designlasin hintakirja by Nanny Still (a very accurate Finnish book with all designs by Still for Riihimaen) - so IMHO its not by Still
Why do I think it is Riihimaen?
Because this vase of mine is in the same grouping in the Miller book and has a Riihimaen acid etched stamp to base - I have two others the same without stamped base so don't worry about that
There were many designers at Riihimaen: Aladin, Okkolin, Siiroinen, etc. I don't know the maker of my piece as yet - so your vase is Riihimaen and may even be by the same designer as my vase :roll: :?: :roll:
This is all just my opinion, others may think differently