Uh oh ... glad you showed us these others. So far everything looks modern.
That Bennington looks very weird -- I don't know what anyone was trying to do with it -- gonna guess it was a recent project though.
If glass, the ones which started the thread could be ground down from something else. Cullet is sometimes ground into marbles and ends up with cool patterns.
I'm not the best person to send marbles to. I would try to look them over and return them promptly but I'm in the middle of packing for a move and not always good with timely mail. *sheepish*