Cedarman is very reliable at his IDs. He's a great guy. He takes it very seriously and does research if he's ever in doubt. I know him from another forum.
Yes, that sure is not usual structure but I can imagine some variance occurring considering. How they created them is really not well known to us and at what, 200 marbles a minute, anything is possible as a variation!! Cool.
Cool marble. I would more call that red translucent as you couldt see objects on the other side clearly, which would be the state for a transparent glass.