The one I have above is "Hot House Glass" I was trying to find another like it but found it impossible, do you have any connects besides Moon marbles ??
Benington's, clays & China mix, yes the China appears glazed to me also, all that means is glaze was put on the clay before firing, all the rest were fired as well
Cat eye, try a neutral colored background like gray, white and black don't work so well, something easy, felt or a blanket or tweel, whatever you have. I've found grey felt works the best. for me
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Looks like a regular clearie or industrial marble, either way a very very low value if any ?? You never know though, keep posting whatever you have