J_Ding

Wondering what maker did this one? The mib is 0.59" and the base glass is very clear transparent with a few fine bubbles. Is this a messed up cat? Seams are tough to interpret as there is some cold rolling around. Might lash a bit and look like an unconvincing Master in the parts I can see. Some of the glass converges at the seams like Master or Euro. Thanks in advance! John

Yes, the gap is helpful! John

I posted another example of an amber two seam slag on another thread on this site, so as to not confuse the discussion. It doesn't have wide swaths of white as mentioned above, but does has a north pole bias to the colorant, and one half does not show it. Swing over to that thread and let me know what you think! John

This is a continuation of the post on the cranberry patch, CAC or German. It was mentioned that often CAC two seam slags had the patch often on only one half of the marble, like this example, on one half of the mib. I have others I take as CAC too, but don't have photos of them yet. I always took this one to be CAC and maybe German. Let's bat this around a bit too. It is 0.73". Thanks! John

This is great discussion, and some excellent examples to fill the mental hard-drive. I rather like a back and forth tennis match over the ID of a mib. The clarity of the glass, while not clear in the pictures above, is quite remarkable. Keep the debate going! So far, it seems a draw.

And lastly (for now), this oddball. John

And another grouping of keepers and of which it seems I only have found few examples (I have a few of number five). John

Just some more Akros. John

And in a Conqueror. John

Super Vitros! This one, a kind of turquoise, in an Akro. John

Nice examples. The color capture in the photos of the marble in question is accurate. Maybe this was one of those, end of the batch, toward the end of one of the colorant kind of events. I was more Akro on the seam and the glass, and more CAC on the horns...but that excellent group of examples you posted of single seam Akros is great, and shows some resemblance to what is going on in the marble I posted, I think. Maybe it fits with those nicely. John

This one, at 0.64" is a mystery. I've posted this on other sites and didn't get anything definitive. A comparable would be nice. The thinking was this, single seam mib was either CAC or Akro. The ram's horns give it a CACish feel, the tiny seam looks more like Akro (and although lashes are found on many mibs, you know, it has those Akro-ish lashes too). Strong UV, predictably, on this one as well. Thanks for the input! John

Hello too! FYI, I'm a displaced Packerlander. I also took this mib to be foreign as well.

Any ideas? It's tiny at 0.49" on the long axis. John

This one, at 0.64" on a transparent cranberry base, might be a CAC, based on the glass, ram's horns and the straight seams. The other possibility is German. If you have photos of another like it, please post. Would like to see another example. Thanks! John

That might be possible, but one problem is that, even for the same marble, there is variation in its construction, and mass. Curiously, when measured in grams to the hundredths position, 0.00g, similar mint marbles, maybe from the 'same run' will have different masses between them (when in mint condition). Also, volume displacement will give you, in the best case, a rounded number to the tenths position only accurately to the tenths position, as near as I can tell. I have graduated cylinders in my lab, but they have to be big enough to accommodate the marble, and then this causes the accuracy of volume measurements to fall. Not sure that I've seen how one could get to the 0.00 position in terms of volume (without cheating!), accurately, by this method. Why does this matter? Well, if I only took density calculation to the tenths because this is all I have for volume precision, then I lose accuracy and most marbles would run up or down and appear to have the same density, when in fact they are different. If one really wants to see how these vary from manufacturer or age, it is best to have as many decimal places that one can...hand calculating volume and mass to 0.00 will give greater precision. I know most people won't care, and that's OK! I still think it an interesting problem. John

I've tinkered with this very question too some time ago, and came up with some data, provisionally. I went with digital calipers, and tried (this is all very problematic, you know) to find the greatest and least diameter, find the average, then get the mass in grams (two decimal places) and use the formula you reference to calculate a provisional volume in order to get the density. I did find some variation (I looked at only pre WWII mibs in this short study) in the density, something like a low end of 2.30 g/cm3 to about 2.72 g/cm3. For machine mades, most came in around 2.35-2.50 g/cm3, while a few ran a bit higher (some Master and Akro). Interestingly, all of the higher density marbles of over 2.60 g/cm3 have turned out to be transitionals, a mix of American and German, but I have had American transitionals also run low (2.42 g/cm3). Not surprisingly, Pelt Rainbos, and their extreme bubbliness makes these run lower in density, as expected, as the glass is replaced with gas in these examples. I also looked at runs of the same type of marble and found that there is also some variation there, but nothing that seems to be important. My wife, who has a good statistics background, ran some simple tests and found no workable significant diagnostic differences within and between groups/types of marbles. In a word, my initial conclusion was that density can't be used in any meaningful diagnostic way, but that there might be useful ranges of densities if enough were measured. Who knows, I have some concern that these objects, imperfectly round as they are, might be difficult to get a very accurate volume on. I've measured several hundred densities of mibs in this way, but I haven't yet done many that I would like to check: slags, CACs, and swirls, of which, I think I haven't measured any yet. This takes a bit of time. So, I guess, I would say, yes, they can vary a bit, and some actually are more dense than others..., but not sure a person could actually tell 'in hand.' John