2 or more points less on the sheldon scale I would imagine. You can't have an ms70 if it has spots, pcgs says themselves it's best to judge the condition yourself since the spots happen after grading. Just because it says ms70 doesn't mean it is.
Walking into dangerous ground brother... If a 70 isn't a 70... If the plastic slab can't protect the coin forever... Why bother slabbing at all???? Quick stone the heretic...
I know that, but try telling that to the person that paid big bucks for it before the plague appeared. And it will still be a 70 on the registry, not that I care.
Yeah, sometimes they are, but a whole lot of the time they aren't round at all. I've seen lots of streaks, even seen examples where most of an entire side of the coin has turned red, the same red as so called copper spots. Read some of the posts I've made about gold toning, and yeah, it does tone. As for thinking about the impurities being stretched out during rolling, if ya really wanna get confused, try thinking about the coin in the 3rd dimension - thickness. And then try to imagine how the impurities just happened to end up in the very top layer of the metal so that they are even visible at all when they show up - especially in metal that is .999 or .9999 pure. And milk spots on silver, they're not always exactly round either. They're kinda sorta round shaped but I've seen tear drop shaped, irregular blob shaped, and round shaped all on the same coin at times, or separately. The reward is for safely removing milk spots - not for preventing them. And not to be picky but the reward was originally $25,000, not $50,000. And unless they've upped it in recent years, it still is.
I guess metallurgy's enough of a mystery to me that I'm willing to take that part for granted. They may preferentially form at the metal's surface, they may migrate toward the surface during processing. And the more you roll out the metal, the more of it becomes surface (that old square-cube law). Sure sounds like splatters to me...
I agree with your last sentence, but migrate through the metal ? The only time that can happen is when the metal is in molten form - in other words before it even becomes metal in the normal sense of the word. Once it does harden and become metal, any impurities are fixed in place. And the vast majority of any impurities are going to be scattered about throughout the entire thickness of the metal in individual molecules, with maybe a few small clumps of molecules here and there. As the strip is rolled out to planchet thickness, yeah some of those clumps of impurities may become exposed on the surface. But when the finesess is .999 or .9999 - there's going to be very dang few of them ! And the odds of a single clump, let alone several clumps, just happening to end up on the surface by chance - are astronomical because of the fineness. But yeah, it can happen. And once the rolling is done and the planchets are cut, visualize the planchet as looking this when viewed from the side, with that small dot in the middle being a clump of impurities - ______________________ . ______________________ You have 2 surfaces, top and bottom, and for copper spots or milk spots to become visible, they absolutely have to be right at the surface of either the top or the bottom. So given the odds I mentioned above, you then have to also consider the odds of a clump or clumps of impurities being right on the surface in that entire thickness. Granted if they are on the surface they can have been enlarged by the rolling. But they first have to be there. Given all of this, you begin to see how unlikely it is for those clumps to be right on the surface, nonetheless, it cannot be denied that it happens for the spots do appear, and way more often than they should ! There's one very obvious possibility, the fineness is not what is claimed in many cases. That said, all tests, and there are tests, seem to indicate that it is what is claimed. I guess that depends on how you're defining splatters. But the word itself makes me think of something being deposited on the surface of the planchet or coin. But if that were the case, then dipping could and would remove them. But since dipping doesn't remove them, it kind of dictates that they are not splatters being deposited on the surface after planchet or coin formation.
See, that's not true, though. Annealing metal definitely causes atoms to migrate. Cold working might or might not, I don't know (one of the many parts of metallurgy I don't know). Is it enough to cause macroscopic impurities to migrate during the normal processing of coin metal? No idea, but I don't think we can rule it out. (I started down a rabbit hole a bit with this. I remembered tin pest, which may or may not be relevant, and electromigration, which almost certainly isn't...) Again, I'm not convinced it's that simple. There are materials that can migrate into bulk metal, and no dip will ever fix that. Think about getting mercury on gold. (I sure hope there's no mercury in the Mint's processes, but there are other materials that can behave similarly.)
I think you're missing my point, but that may be my fault for not making it clear enough. Even if you're correct and atoms can migrate through metal, I somehow doubt that because solids simply cannot move through other solids, but for the sake of argument let's say you are correct. When milk spots and or copper spots form on coins of .999 or .9999 fineness - we're not talking about atoms migrating here. We're talking about entire solid clumps of impurity, roughly the same size as the resulting spots, migrating through another solid. And that just isn't gonna happen as a result of the planceht being heated up. Wherever those clumps of impurities happen to be in the planchet, that's where they are going to stay. In addition to that, if it was just atoms of impurities somehow migrating to the surface during the planchet being heated, those atoms would then somehow have to manage to migrate further, possibly even sideways, then somehow congregate together and form good sized clumps before you could even see them. You can't see atoms, you can't even see molecules. What I'm getting at is we're talking about clumps of impurities that are at least as large or larger than the period in this sentence. And those aren't going to migrate through another very dense solid just because it gets warm during annealing. So yeah, I think it can be ruled out.
Oldest Milk Spot ? Didn't want to give this it's own thread, but at what point is it pretty likely (I realize there are no guarantees) that if you don't spot by then, it won't spot ? I ask because I bought a 1987 Proof ASE this weekend. One of the reasons is it's been 33 years and it's still blemish free. I got a milk spot on a 2014 Panda that I bought in early-2014. Now, when it developed the milk spot I can't say for sure -- I just looked at it this weekend after years of not looking. Figure it probably developed after 2-4 years, I would say. Can you imagine paying $1,500 for a PF70 2019-S ASE and then getting a milk spot 6 months or 2 years down the line ?