The surfaces on this silver proof coin are puzzling to me: http://www.ebay.com/itm/Korea-1970-...114483?hash=item3f72b093f3:g:8I8AAOSw8w1X64uf I really wonder what's going on with the whitish-ness in the fields of this coin, which is extensive. I know that this coin, probably because it was a separately-sold commemorative piece, was most likely kept in a supple, clear-plastic envelope. Is this the result of PVC breakdown on a proof-silver surface? Also, there is, what seems to be, this big scratch at 4 to 5 o'clock: I just wonder how it got a grade of PF-63?
And keep in mind, 63 is a near-insult as a Proof grade. The coin definitely took a heavy grade hit for the marks and haze.
I don't know exactly what caused it but it's super common on 70s and 80s US proofs. I know it can be removed from those coins by dipping.
Struck at the German State Mint in Karlsruhe, under contract for Italcambio; the Caracas-based organized-crime linked commemorative world-coin distributor extraordinaire of the 1970s. If these are striations from polish lines, they'd show up as relief lines on the coin, right? Now you really got me wondering...
They should show up as raised lines not scratches into the coin. I'm curious. Since this coin was struck at the Karlsruhe mint...does it have the same "G" mint mark as German coins?
In my research on these "5,000 Years of Korean History" 1970-dated South Korean silver commemorative coins, the only mintmark that any of them might have is the "1 AR" mintmark of the Gori & Zucchi Mint in Arezzo, Italy. Some of these coins were minted there, and I'm guessing, that all of these have that mintmark. If they don't have that mintmark, I'm guessing that they were minted in Karlsruhe. Lots of guessing on my part. Since these were done under contract at various locations in Europe, tracking down information with precision would be difficult and possibly expensive. I also know that two locations are cited for the minting locations for the gold coins of this series: The Valcambi Mint (Switzerland), and the Paris Mint. The Paris Mint versions of the gold coins from this commemorative series are highly prized, since their mintages are 100 to 25 pieces only. These have that Paris Mint "cornucopia" mint mark at the 8 o'clock position on the reverse.
It's not mysterious at all, haze is the beginning stage of toning. As for the lines, based on your pictures I can't tell what caused them for sure. But there's a fairly easy way for you to find out if they were caused by the die or not - look at other examples of the same coin. If similar lines are present on them as well, then the lines were on the die. If they are not present on others, then the lines on this one were caused by rough handling.
I've noticed these hazes come often when silver coins are put in a "reused" acetone bath. If some dirty-ish or seemingly non-dirty coins are put into an acetone bath, and the same acetone is used to put in a few other proof coins, those proof coins exhibit a haze just like that. It often even develops into a swirly and colorful oily looking tone. Maybe that's what's going on here.
Here's that same coin, but as a "toner." Not milky, but rainbow-ish. So, this coin, too, was once milky? http://www.ebay.com/itm/Korea-1970-...369758?hash=item3f67f9e41e:g:mAgAAOSwH3NXn3b2 And this one has that "1 AR" mintmark of the Gori & Zucchi Mint:
Not exactly, that's how toning on Proof coins often starts. I won't say it starts that way on every single coin but it is extremely common. That said, if you look at the coin found on ebay that you just linked to, the blowup pics anyway - http://i.ebayimg.com/images/g/dDEAAOSwIgNXn3cD/s-l1600.jpg - you can see some scratches in the fields underlying the toning in a similar location as those on your coin. But since the two coins are from different mints rather obviously it cannot be said that the scratches on the coin came from the die - since they were both struck with different dies. And the underlying scratches on the toned coin form a different pattern than those on your coin as well. Give that, and the fact that the obv of the toned coin also shows scratches in a few places in the fields - http://i.ebayimg.com/images/g/6zEAAOSwnQhXn3cA/s-l1600.jpg - I think it reasonable to assume that the scratches on your coin, and the toned coin, came about as a result of rough handling, as opposed to being die polish lines. And though I can't prove it of course, given the look of the toned coin on ebay, I'm pretty much convinced that it is/was intentionally toned that way (and yes you can read that as AT) in order to try and cover up those rough handling scratches.
Thanks for the info, Doug. I also wondered about the color and the fact that it has this "uniform" pinkish look to it. It also doesn't look like other toners of these same coins that I've seen in the past. They seem to tone dark in patches, not pinkish-blue.
It's not the color that makes me think it's AT, it's the way you can see traces of the liquid used to do the toning, in particular just below 3 o'clock and close to the rim on the rev.
Hmm. And around the legends at 12 and 6 o'clock, it looks like this "toning" is the remnants of some liquid that dried up. Almost like the "reused acetone bath" that iPen mentioned above (post #13).
