Not sure about whether it's a double ingot or not.
As to age, the textures and the two colors of ribbons are making me think newer. But I wasn't able to recognize a possible style name when I looked at the billes-in-tete site, so I don't know.
Hmmm ... more views might help.
I'm having trouble making out the structure. This might be a double ingot. Do you know what that is? It's where the glass for two marbles got fused together to make one big one.
#1 Japanese transitional
#2 European Striped Transparent
#3 Maybe Japanese transitional, but I'm wondering if it might be a Christensen American Agate
#4 ???
Ricardo Mendoza over on facebook reminded me of a category that we haven't talked much about.
His childhood collection of Vacors (from 60's and 70's) has a whole lot of very colorful Sunbursty looking marbles in transparent matrix.
I'm wondering if some of the egg shapes we are seeing in the picture are a camera illusion. I would get egg shapes on the edges of pictures when using the macro lens on my last camera.
You have them in hand and you say some are out of round ... but I'm wondering if maybe not as much as they look in the pictures.
Just a thought.