Wow. Good article. Finally getting mainstream press! About time http://news.coinupdate.com/milk-spots-on-modern-silver-coins-how-big-of-an-issue/
"The Perth Mint has also taken steps to both identify and try to tackle the problem. Two years ago officials at Perth said that, after ruling out suspicions of "poor water quality and crucible contamination," that "an accumulation of microscopic silver chloride debris are responsible for leaving the blotches." As a result of these findings, the mint implemented some measures to reduce the frequency of the spots, including "routine cleanings of its airline filters so as to remove any oil and water build-up" and "replacement of its air conditioning filters" to eliminate the chances of "airborne microscopics" appearing in any of the areas where coins are made. Those efforts appear to have been successful in reducing the number and frequency of milk spots on coins from Perth, but according to many posters at the SilverStackers forum, the issue continues to plague coins from this mint. I found their comments surprising, since I have not seen a lot of spots on Perth coins I have purchased. LOL, I'd say this is a direct reference to the recent Perth Mint Milk Spot discussion thread I agree with this author, I too have not seen a lot of spot on Perth Mint Coins, but obviously a lot of members here have
A different theory: Mechanical polish vs. chemical treatment. So maybe the problem with pollutants has always been there, but the change in the minting process makes spotting more likely to occur now.
I was just about to share that article when I saw that barsenault beat me to it. A couple of take-away points: 1) lots of people read comments on the SS forum but probably never chime in....which is fine. 2) the more the issue is discussed intelligently, the more likely knowledge about the exact cause will come to light and hopefully, if buying patterns change enough, the mints may (as unlikely as it seems now) need to much more strongly consider how they manufacture coins they sell with a collector premium. .
Poor water quality of Australia is much better than China. Panda coin mint in Shanghai, Shen Zhen and Shenyang which those cities are well know in air or/and water pollution. Anyone has statistic of complaint of white spot of Australia bullion coin vs China panda coin? WHY white spot happen more often at bullion coin and NOT proof coin? This puzzle me
This is me, however I do come here for the information. The level of knowledge continues to suprise me. And thanks for posting the article too OP.
Quality of water could depend on how the water was cleaned/filtered/purified, rather than how dirty the source water is.
not to worry there.these spots are everywhere.proof coins are not exempt either. But one thing makes me wonder how come I have never seen any spot or toning for that matter on any proof coin made for Tuvalu and such-if Im correct perth mint makes them too.just grab any BU or proof coin which says Tuvalu o back and you wont find any blemish. same thing apply for the olympic 16 coin silver set.
Even drinking water quality of those big cities if china is in questions. You can imagine of the it. How worst Australia water quality versus china. Easy answer
Another place I have seen no milk spots is 5 oz ATB Uncirculated P issue coins. Can't recall seeing them on bullion versions either.
^ I have seen many ATB "P" 5 oz coins and have never seen milk spots on any of them. My guess is that if these coins were ever to be prone to some level of milk spotting, the vapor blast finish would all but completely eliminate any chance of spots developing. I think another member here stated that he'd seen a few of the bullion version with what looked like milk spots. I don't have much interest in the BU version and so I have not seen a lot of them....it is possible that the BU version has some minor spotting issues and if the "P" version does, it's likely to be a very rare instance. Come to think of it now, the fact that the "P" version coins haven't been plagued by milk spots like most other silver bullion coins from around the world have, it's a good selling point for bullion coin dealers to take advantage of. .
Most of the regular ATB won't have spots as they have been rubbed off. These coins in the original plastic cases are so scratched and battered it's a joke. They give new meaning to the word bag marks. This whole thing is a scam. The water has not changed in Perth since 2000. The number of milk spots in pre 2000 coins is almost 0. From 2000-2008 there is the odd 1 or two that I have seen. From 2009 onwards it starts and certainly by last year 2016 it was epidemic. It was hard last year to find a newly minted coin without some spots especially those bigger coins like 5, 10 oz or 1kg. Let's look at some facts: The water used in coin production is filtered and de-mineralised. All coins, proof and specimen / unc get it The white colour is a precipitate of silver chloride one of the least soluble compounds known. Spots are not removed by acid, alkali (NaOH), solvents (acetone, xylene) or alcohol. PCGS can remove them by some method ? Which does not remove metal or damage the coin The only way known to remove these marks (other than PCGS) is to use some abrasive method which destroys any numismatic value These spots do reduce the numismatic value dependant on size, number and position. There is 1 obvious fix : DONT BUY ANY NEW COINS FROM THE MINTS UNTIL THEY FIX THIS. BUY BARS .....OR OLD COINS
Ronnie, the BU ATB's very often do have lots of problems but I have seen some fresh from a tube in super nice, nearly flawless condition. Those are the ones that get the MS69DPL grade. That said, there are none that I'm aware of that have ever graded 70. Under 5X magnification, likely all BU versions have some sort of imperfections. On the other hand, I have held flawless (under 8X and 10X magnification) "P" version ATB's in my gloved hand. So I know that the "P" versions are in much better condition from the mint. This makes a lot of sense and hence the higher premiums. As for milk spots, I will take your word that it started getting noticeably worse from 2009 onward. My guess is that it's not the water but rather the mint may have simply started cost cutting by cutting corners (not rinsing the detergent or whatever). That's almost always the culprit in a sudden decline in product quality of this nature. .
A favor for the entire community please: For those who purchase lots of Perth Mint bullion coins, please make a short list of the coins that you believe (based on your observations) have the most milk spotting problem. The more people who compile such a short list, the better idea we can have of which PM coins are the biggest problem in terms of spots. For those who purchase lots of Royal Mint or Royal Canadian Mint bullion coins, please make a short list of the coins that you believe (based on your observations) have the most milk spotting problem. It will be interesting to see when we compare lists, if there are clear winners (far less spot problems) and losers among bullion coins. .
Can we oso include toning? My observations across the trades: 1) WHITE SPOT: - S2 Lunar dragon 1oz bullion - S2 Lunar Goat 1kg - RCM Maple and all recent years wildlife series bullion 2) TONNING - S2 Mouse 1oz bullion - S2 Snake 1oz bullion
Bummer about the colorized Dragon. What size is it? I checked some 2012 1 oz High Relief proof Dragons last night. No spots. On another note I checked some 1 oz bu Pandas. The 2012's had some spotting. I've got a couple 2008 slabbed and they're fine. 2011 2 oz Proof Libertads were also fine.
