Pattern looks CAC. If that's crazing in the glass probably didn't make it through quality control, and might have been in the ground? both that and iridescence can be caused by being buried. Nice looking marble though, do you remember where you got it?
Interesting, never had one before and always assumed they were a polished mineral sphere, similar to a tiger eye, Agate, etc. Wouldn't have suspected glass. Learned something new.
The first marble I'd put with my Pelts. Sweet pattern, especially 1st pic.
The others I'd put with my "wants to be a Pelt, probably isn't, but really wanna be" pile. Oddly enough Imperial came to mind, and then MK...then Vitro, then full circle.
tough to say without seeing in hand, but the size and pattern lean me towards handmade. See if you can find evidence of a pontil, in the area where the red ends.
When you put a light behind it, does the construction twist from pole to pole (ie: where the red stripes stop and, where they begin at the opposite pole)? Almost looks like it could be a handmade but hard to tell from the pics.
Beat me to it, my opinion is the same. Although the color/pattern is usually more associated with the other transitionals I think this predates those, and German in origin.
Agreed, Vitro (with a slim chance of Pelt) on the right. Left looks a bit wonky.
Have you tried a flat (non-textured) background? Gray usually works best for my camera