Hello Mario, not sure if you have been welcomed to the glass message board but welcomed you are.
As you may now be aware values of glass is not really commented upon here as it is so subjective.
I love Oiva Toika's work and have one or two items of his work.
Do you know the age of the item you have?.
As to getting a value for your glass , there is a dealer in the Netherlands called, glas-desgn.nl they may be able to help you.
All the best,
Tim