Alan

From the second photo we can see fine wear across the glass surface without much in the way of impact hits. That suggests that it wore for some time against something abrasive - probably other marbles, or it was lost in the dirt over many freeze-thaw cycles, and then later found.

Opinion: Its only worth $50 if there are two twenty dollar bills under those marbles.

(Unfortunately, I have chosen to remove this content due to unchecked behaviors by others on this board. My apologies to those who will not benefit from it in the future.)

It looks contemporary in those pics - but the color saturation looks way too artificial to represent real glass. What did you do make it so? HDR and a light box?

(Unfortunately, I have chosen to remove this ID content due to unchecked behaviors by others on this board. My apologies to those who will not benefit from it in the future.)

Nothing wrong with a 5MP camera. A well-focused and lit 5MP pic is far, far better than a fuzzy, out-of-focus pic at 3 times the resolution.

Those pics are almost all out of focus - but it doesn't appear so. Center select your focal point and back your camera away until you are within the lens focal length.

(Unfortunately, I have chosen to remove this content due to unchecked behaviors by others on this board. My apologies to those who will not benefit from it in the future.)

The bottom left doesn't look like wear. It looks like multiple impacts. I'd say "walk away". "Don't sell a marble to yourself".

Is that some plastic film adhering to the Onion - or has it taken a good beating?

Its missing the wispy white that would make it a Popeye. Plus as noted before, its not a corkscrew.

The vast majority is ballast. The handmade pic is out of focus, so I can't estimate condition. All the same - its a common. Anything over $20 is charity.

The sacrifices are significant and pretty much every day. All gave some. Some gave all. Proud to have served and sacrificed.

Modern MK.

The concept of "same run" for machine mades is a red herring. Marble types were intended to match a desired design. In almost all cases that design ran for a very long time (think in terms of a year or years. Rebuilding a pot doesn't mean that a design dies out. Relative consistency was a goal. Retailers ordered what they wanted. There is no reason for two marbles made a year apart to look significantly different, small variances aside.

As you are no doubt noticing - the problem with maglighting is getting the camera to actually focus on the structure of the marble without blowing out the details and causing them to end up blurry.

(Unfortunately, I have chosen to remove this content due to unchecked behaviors by others on this board. My apologies to those who will not benefit from it in the future.)

Technically its a "punty" mark.

Very new weight. High speed, low cost mass-produced type.

If a marble is not fully annealed, or if glass compatibility was an issue - then stresses in the glass can remain. Those stresses may be minor - or a borderline problem. For the latter case - it may just need a physical shock or temperature shock to push those stresses to the point where a fracture occurs. I once had a newly-purchased 7/8" Akro Vaseline auger pop in half in my hand as I washed label adhesive off it with warm (not hot) water. I've heard of mailed marbles fracturing when shipped in winter.

Internal stresses from oven brick and air interfacing with glass as they cool at different rates. With different coefficients of expansion - that stress can fracture glass.

Can you provide a link to whatever it is?