If the marbles were sold separately with good photos, I think maybe they could net more than 10k$.
I'm not sure though. I'm definitely not in that market.
The 52k$ marble was a ploy for the seller to get attention for his ebay sales. It worked!
Here are the photos which prompted my question. Trying to help someone sort out his banana-types. The black in this case turns out to be purple-tinged.
I think I have some foreign ones. So I know not _all_ would be Master. So of course my question is specially about the American-made ones. Which I like to think I can identify by the color of the base glass.