This would be so much easier if we were next to one another holding that marble, but I'll give you a couple of tips. First, I have seen that "thick multi-filamentous wispy striping" (for lack of better terminology) on quite a few Alleys. And second, if you look at the cut-off (seam sorta) on the top of the marble as you posted it, it sorta looks like someone dragged a butter knife through the hot glass and the "striping" is kinda drawn out to fine points.
I hope this helps - it's tough to put it in words.