I bought this some time ago in Belgium, although the seller thought that it had come from the Netherlands originally.
It's a whopping 26.5" / 675mm tall, an elongated and completely undecorated egg-shaped bubble of opal-white glass with a small clear glass foot. The foot has been cut and polished to the base. Bit of wear to the base, but nothing drastic.
Signed indistinctly to the side - looks like Aanms/Hanms/Aamms/Hanms/Hamms... or any combination thereof. It's yielded nothing in my searches.
Any help gratefully received.