Our long Realers thread with the Glassonix discussion disappeared ... and I need a place I can find easily where I can replace some of the pictures which were there. Here's one of the pictures I was looking for. (From 1930.) Another was a small ad maybe from Playthings Magazine. But I don't have my extensive archive uploaded to this computer yet so it might be awhile before I can restore that one. Any help or any new pix are welcome.
The picture links didn't work for me -- tried to see if I could fix it from looking at the code, but alas I could not.
I can almost see the marbles just from your description, though.
I'm not an expert. But I think it's "copper oxide" or "cupric oxide". CuO. I think that gets your turquoise and green.
And copper in a more pure form may be used to get reds.