Hi dmst and welcome to the board

I cannot help with identifying your pretty vase but hopefully someone else will recognise the technique and be able to help you.
I don't think there is an N mark on the base. I think it is where the pontil rod has been neatly snapped off and leaves the pontil mark.
It is opalescent glass with what looks to be burgundy or dark red iridescent casing at the top and trailing to match.
I am wondering a tiny bit about Poschinger as they did make something similar but I don't know if they used these colours or if they left their pontil marks like that.
I hope someone else will be able to help you more.
m