Your vase is like the work of Campanella in having the thin ends of the facets end in a line, instead of a point (as is the case for Mandruzzato). I have seen a couple of other companies that do their facets the same way, though, so I can't say with any certainty that it is Campanella. (If I remember right, the other companies were Bucella and Nason, but I'm not sure. I'll try to locate some pictures.) Vases that have the facets ending in a line have eight sides on the base -- 4 short, 4 long. Contemporary Mandruzzato facets end in a point, so the base has only 4 sides.