The weight difference between a 2" soda-lime marble (~173 g) and a 2" lead crystal marble (~186 g) is about a 7%. But it would be like trying to distinguish 34 nickels in one hand from 37 or 38 in the other hand based on weight. I am not sure I could do it.
It's a good approach, but my calculations yield ~173 g for a 2" soda-lime glass marble (68.64 cm3 and your s-l density). As for variation, it would really depend on glass density and additives, as suggested. A lead glass 2" could go well over 212 g. And small variations in size are significant - a 2.05 " s-l would be ~186 g.
Now look here, Steph, you can't just say something like that, like it's 'just' dark blue AV on an Alley. Seriously, and then not show us a pic! I am telling you, it's almost inhumane.
Bill, you must owe me a marble. I'll take the cow.
I am having a hard time making out any distinguishing features on the lower left one but I think the one to the right of it is Champion. I also think there are JABO Classics and others that aren't Alley in the group. Maybe I'll take a shot at better IDs later.
The Big 38 is a great bag. Does Dani still own it?
Darla, the base on that Tater Bug looks pretty different, not like I am used to seeing.
Nice oxblood all!
Ron, Now you have me thinking about Winnie's marble and the one you posted. I was thinking Winnie's looked like a weaker example of that big bad AV I got in that first small group of Sistersville's - you know the one. But it looks a lot like the one you posted, which is odd. Maybe you could bring that one along for comparison?