I think that Master Made Marbles is a good call here.
I can see the hardness of the glass (just my eye)
Master Made Marbles manufactured some very indestructible marbles, they still hold up quite well to this day.
The red one looks like the glass was very well “cooked” before it was run into the process.
Like I said—just my eye—all opinions are welcomed and appreciated.
Marble—On!!