That's a very nice flame. From the picture it has a contemporary look to it, but I know you said it is not. I'd guess if it is older that it is by one of the lesser makers we see whose marbles have flames. Ravenswood? I would doubt it because too much clear glass base. Cairo or Heaton? Maybe, but not exactly their MO if you know what I mean. It looks like the marbles kind of that you find in those USA boxes when they have the legit marbles in them. So, who made those? Ravenswood? Champion? Heaton? Cairo?
I'm not much help but it's a nice flame regardless.
Ron