One of the few pieces in my collection which, though being distinctive and well made, escaped ID for many years now.
Vase with narrow neck, fairly lightweight, dark blue glass internally decorated with bubbles and powders. (Hard to see in normal light due to the rather dark colour).
Stands 30 cm tall, base polished with at circular polished pontil mark.
There is a mysterious label attached to the base, which says
5032/260
BL oxid
20:50
Looks to me like a pattern number (similar to the ones used at Skrdlovice for instance) and probably a decor name / chemical ingredient?
My thoughts so far regarding the decor: Murano (Barovier "Efeso"), Germany (Gralglas, Peill and possibly others), Leerdam, or maybe a Scandinavian maker?
But no convincing ID so far...
Thanks for any thoughts!

Michael