Loetz Metalic #6: Perlglas

I remember the first time I saw them, I couldn't understand it....Why would vases be placed so high up in a glass gallery? Novicheck Galerie in Vienna, early 90's... just a backpacker asking why these vases were so special. Apparently these pieces are not even considered Loetz because they have such a special process, special production numbers and designs- it's true! they have shapes I have never seen with other decors on them. I was told the actual bubbles contain mercury (pretty dangerous stuff even for glass blowers of that time). The price? he didn't even want me to know...