Alan

Nice!

Akro didn't do "runs". They ran machines for extensive periods until the pot slowly dissolved and the firebrick ended up in the glass, signaling that it was time for the pot/crucible to be rebuilt. That rebuilding was a big effort and meant that it was down for weeks. Vintage marble making made marbles for small fractions of 1 cent. They fulfilled very large orders. They did not do short "runs" This concept is an invention. This is a recent invention. If someone disagrees - please ask them to provide Akro documentation that validates this new claim. I'll be interested to read it. Otherwise, its just an invention to create the allure of rarity and hike the asking prices. Folks shouldn't be taken in by these stories. "Every questionable marble sale needs a good story to support it. A good marble needs no story at all".

Odd colors. I see the hint of Master glass flow, but I'll defer on an ID attempt. Perhaps somewhat brighter lighting may help.

This is a form of junk science spewed by a Google AI bot, then seized upon by an inexperienced person who only has that to lean on. I suggest you defer trying to invent new specialized naming to a marble in front of people with decades of hands-on experience that tried to guide and advise you - and you continue to ignore. It's the same glass/marble that I and several other people here have owned, handled and known for decades. It may be new to you, but it isn't new to the rest of us.

You are forgetting mid-years. And really, early mid- and late mid-years.

Oh please......

I have to ask where specifically you sourced this information from (I assume an Akro glass formula book) and the diagnostics that are used.

FWIW - Akro Vaseline glass is actually transparent, not cloudy/fairly opaque as the original photo. It can become the latter of course. (Akro)

Did you do a chemical analysis of it?

Are you collecting - or accumulating?

Looks like a swirl that corked on the rollers (that happens).

Not a Lawn Chair.

I am questioning the AI quotation that MK owns the BL brand as a sub-brand. The BL marbles pictured above are torch pieces, not tank marbles.

I agree with what was said here - and nothing really to add. When you see that iridescent sheen/reflection - think "modern".

Your camera keeps guessing at what you want in focus and exposed properly - so it is choosing the background. Note how it's details are in-focus. The flash is firing to expose the background properly, washing out the details in the marble. Try daylight, flash off, non-textured neutral gray(ish) background and (most importantly) manual select center focus. That will set focus & exposure. Look at the details of the marble on your camera screen before taking the photo.

All of the pics are at least slightly out-of-focus. I'm getting a 'new glass' impression, but I'll hold an opinion in hopes of focused pics.

The particulate is oven brick from the pot dissolving.

Post Civil War, as noted. Pics are out of focus and too much flash, but appears to be a solid core.

Far more likely that some ended up randomly in the clear cullet pile.

The ones I saw were in brag boxes and NFS. I own weird manufacturer stuff that really aren't money pieces - I just like them. I think the ones with screws are like that. (I'm still negotiating the possession of a 60 lb. set of marble machine shears 🤪 )

The condition makes this more challenging than usual. The color and saturation is strongly suggestive of a cane-cut Opaque (not sure if the shear marks remain). Assuming I'm right, the color is harder to find than most, although the condition is obviously problematic.

Crud from the cullet pile. I have seen a few with screws - always wanted one.

Ice skate sharpener.

FYI - a black background will usually overexpose the marbles and blow-out the lighter highlights and details.

I recommend using quality UV safety glasses when using 365 nm flashlights.