One can never be sure of course, a lot is not listed, catalogued and documents/drawings lost, and it took me a while to say something because it's a tricky one.
Before the 20ies, around 1900, they did use Vaseline glass and the above mentioned colour too, but patterns were either much richer and detailed, or with more sweeping facets and cut lines, very much in the art nouveau and transition period style. I can't help feeling, and I'm not criticizing this piece, that it's pattern's a bit simple for it to be VSL of this period and there's a lot of space left untouched.
I'll continue going through my books etc. to see if I can at least find the pattern back or something alike, whether it's on a similar item or not, but so far I haven't spotted anything. I don't know how other houses worked, but at VSL a pattern was registered and can be found back on different items, which makes it a bit easier to identify or attribute an item, as not everything was signed at the time.