Yesterday I saw a couple of blue clear-cased vases at a flea market in Bern. One of them is fairly well known, 6" or so, cup-shaped on a clear base with 3 "peaks" on the rim (sorry, can't find an appropriate photo at the mo' since I'm away from home). The other was very similar to yours. Both had Zwiesel labels. From the 70s, I'm guessing.