Alan

You already have a thread in this section on the left one. The right one is non descript in that pic.

$200 is highway robbery and taking advantage of people. Avoid such sellers - know about what you are thinking of buying before you part with your money. At a tenth of that price it is a paperweight. Walk into any marble show and you can find a simple white latt in that size.

It appears to be a normal latticino core that went through World War II. In that condition it hard to understand why anyone would want it for any reason (at any cost).

It is modern. Value is limited.

The brown is just some stray glass from the pot. These days - one is best off not believing seller's descriptions. Adding/stacking word descriptors seems to be taking-in buyers now more than ever.

A hybrid between which types?

They are air bubbles. If you hope for something, you'll see things through that filter.

Not MK, not oxblood.

That would seem odd for Akro glass, IMO.

Is it possible to see it lightly moistened?

Its just some glass between colors. Not unusual, and not a third color. An Akro glass pot wasn't a place of glass perfection. Neither was the cullet pile.

Y/G Popeye.

Not Akro glass.

They appear to be stuck to the surface - at least in one pic. I'm not even sure they are marbles. They look like mill balls.

If the light is blue or violet, it is a reflection. In any case, UV reaction isn't an indicator of anything special.

Swirl, not a cork.

Just a purple machine made clearie with a cold roll.

To the OP's question: These days - new collectors want "stuff" in their marbles. They want what they think is premium....what they think other people want/don't have. And thus having "stuff" in their marble is desired. So called "aventurine". "Lutz". "Mica". etc etc. It has become "What the cool kids have". There is little rhyme or reason to it beyond catchy words. People chasing oxblood are so eager for it that many things red, brown or dark red are frequently mistaken for "oxblood". Eager for it, people see things through that hopeful filter.

This is correct.

Consider the possibility (however small) that it may not be clay. In the pics (which may be different than in-hand) the graining seems exceptionally dense and fine - and therefore hard. I think there is a possibility that it could be porcelain.

"Mint +" That is the sound of tap dancing. WTH is "Mint +" ????

I love photos like these where the prospective buyer has no ability to determine their condition.

That's interesting, because I don't care if it has any UV reaction at all. (Its not as if UV is a determinate of age, value, collectability/rarity or manufacturer). Backlit photos on the web almost universally take the prize for the worst photos available. Focus, exposure and the ability to ID it backlit is usually miserable.

Dug Akro.

It looks like Akro glass. Possibly a wonky flop-over cork (you can see the fold line).