With respect Nancy, I cannot agree with your hypothesis and have to agree with Chip that "not all American Brilliant Cut Glass Co's glass fluoresced"
I have just conducted your experiment, in total darkness, as you suggested, with a wide range of cut glass including known ABC from c1887 and a piece with a silver collar hallmarked 1903.
All showed a reflection of the purple color of the black light. This is what I believe you were seeing when you said " ABP will floresce purple". It is NOT flourescence but reflection.
None of the pieces I tested, older or newer showed any shade of green.
I am informed that there were 3 periods of ABC. Tuthill belongs to the later 3rd period, when designs were less crowded.