Exclusive to silverstackers electron microscope images of white spot

Has anyone tried to simmer new unc coins in distilled water? This would possibly indicate outside contamination if they do not develope spots if a control group from the same batch do develope spots.
 
We use distilled water in all processes, the factory guys are checking for these sources of contamination. It is an ongoing review of the steps in the process.
 
bron suchecki said:
We use distilled water in all processes, the factory guys are checking for these sources of contamination. It is an ongoing review of the steps in the process.
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I appreciate that the Perth Mint is taking this issue of milk spots seriously. It is an attitude of accountability like this which maintains me as a fan of the PM's bullion and proof coins from the Lunar series as well as other series.

I encourage the Perth Mint to continue to do everything in their power to locate the source of the contaminants.



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I'm new to this milk issue, but it does bother me too. It will discourage me from purchasing the higher premium coins, unfortunately.
 
this maybe a long shot but I have had some exposure to dissimilar metals causing galvanic corrosion such as aluminium with stainless steel causing corrosion over time. Now when you reference silver with any other metal other than itself you have a corrosion potential, check out the chart below. So just curious as to what the stamping die material is and also what mine the silver is sourced from, for instance I know the Olympic Dam mine Silver is mined and produced mainly as a co-product of copper, lead, zinc and to a lesser extent, gold. Its main source is silver minerals in lead ore. So from this can we presume that the 0.001% non silver content could be part lead and this maybe is what causes the spotting which does look more like corrosion to me than an algal bloom?

corrosion.gif

Source:
 
Some more electron microscope images and research by a Chinese mint (2011): http://www.cspt.org.cn/fileup/PDF/2010015.pdf

Maybe someone can translate the document?


CORROSION SCIENCE AND PROTECTION TECHNOLOGY
Vol.23 No.2 Mar. 2011

Characterization of White Corrosion Spots on Souvenir Silver Coin

Shenyang Mint Co. Ltd, Shenyang 110042

Abstract: Morphology and chemical composition of the corrosion spots on the surface of souvenir silver coins were examined by optical microscope(OM), scanning electron microscope(SEM), elec-
tron microprobe (EMPA), X- ray photoelectron spectroscopy(XPS), and X-ray diffraction(XRD).

It was found that the silver was sensitive to the presence of Cl XPS and XRD analytical results showed that the white spots were consisted of AgCl Ag2S. The white tarnished complex on the surface of silver was a series of electrochemical process that required the presence of chloride, oxygen and sulfur.

Key words: silver coins; white spot; silver chloride; silver oxide; silver sulfide; electrochemical corrosion

Jc8cdWu.jpg


4TnAH5S.jpg



From another forum:

Summary and comments of the article.

Summary:

1. The article has further provided the scientific evidences that the formation of white spots can be relatively easy. The white spots can be formed as short as few days after the production of the coin, usually in several months.

2. The composition of white spots is silver chloride and high humidity is required to promote the formation of silver chloride. The source of chloride, suggested by authors, is from environment pollutants.

3. The change of minting process of forming mirror surface has caused more and quicker white spots formation. The old method in produce mirror surface was mechanical polish. The current method is via a chemical treatment. Apparently, according to the authors, the chemical treatment produces a rougher surface than mechanical polish. It is known that the moisture can adhere to a rougher surface better than a smooth surface, therefore, the reaction of forming silver chloride film on the silver surface is being accelerated.

4. The formation of silver chloride film on the silver surface retards the formation of silver sulfide (the usual rainbow toning on silver coin caused by sulfur in the air after aging). The white spots will stay as white and size enlarged with time in a high humanity environment.

Comments:

1. The article is in consistence with the observations that the earlier MCC do not show white spots as often as MCC produced in the past few years.

2. IMO, the major source of chloride is from human contact. This article, similar to previous articles (two articles mention by fwang2450 in reply 11 of this thread), has detected significant amount of sodium, carbon and sulfur, the basic element of human fluid, in the white spots. The observation of most white spots developed near the rim and edge suggests the introduction of sweat (sodium chloride, salt and moisture) during the hand holding inspection of coin by staffs of Mint and grading company.

http://china-mint.info/forum/index....21517cc46b262934&topic=3645.msg56299#msg56299
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I see milk spots being a catastrophic failure in the manufacturing process. I had a roll of the philharmonicas and all were covered in a cloud of this horrid white stuff within a year of purchase. I'm amazed at how the issue was not investigated and addressed as soon as it became known?? I can't see how it's acceptable to let this white crystal disease infect the manufacturing process.
 
I have moved back to bars rather than buy coins. Dealer did not advise me of white spot problem. Not impressed.
 
So here it is! The old milk spot problem is already in Russia. Just post a video of my several George Victorious coins with milk spots. And I know for sure that Russian mint doesn't use Canadian Royal mint silver blanks ;-))

https://youtu.be/AjTjrL8u8gU
 
Seems as if the mints don't care so long as they can sell the coins.

If only collectively we could boycott the products that have the most milking issues to a point where it affects the mint's bottom line......but I doubt that will happen.



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mmissinglink said:
Seems as if the mints don't care so long as they can sell the coins.

If only collectively we could boycott the products that have the most milking issues to a point where it affects the mint's bottom line......but I doubt that will happen.



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As Royal Canadian Mint produces Silver maples as cakes it seems that they sell very well. In my opinion it is because the customers are not aware of the milk problem with these type of coins too.
Made a video of mine 2014 horse privy "The milky Queen". Maybe it will help to save your money!
P.S. For me I'm already boycott the products of RCM except simple bullion ones. They simply bought me with that security features.

[youtube]http://www.youtube.com/watch?v=fHi5QchJH_A[/youtube]
 
kutylin, that's some serious milking on the Queen in the video.

I thought I was never going to buy another RCM bullion coin again but then I saw the 2016 Cougar and well....it's a beautifully designed coin. So I purchased some high graded ones. The 2016 Cougar coins are completely spot free. I have sealed them in plastic now and put them in my SDB. In a few years time I will take them out to check if they are still spot-free.


I have never bought into the marketing gimmick of the privy marks. I don't own any 'exclusive' privy mark coins and I never will buy any. Now of course the Silver Canadian Maple Leaf coins from 2014 and onward do have a small laser engraved maple leaf security mark with specific year inside the leaf. This mark may look like a privy but it isn't and therefore it's not a marketing gimmick....it serves a specific security function.


I see in a couple of your other videos you are a collector of the ATB 5 oz silver coins. I really like this series too.....the US Mint's first 5 oz silver coins.




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mmissinglink said:
kutylin, that's some serious milking on the Queen in the video.

I thought I was never going to buy another RCM bullion coin again but then I saw the 2016 Cougar and well....it's a beautifully designed coin. So I purchased some high graded ones. The 2016 Cougar coins are completely spot free. I have sealed them in plastic now and put them in my SDB. In a few years time I will take them out to check if they are still spot-free.


I have never bought into the marketing gimmick of the privy marks. I don't own any 'exclusive' privy mark coins and I never will buy any. Now of course the Silver Canadian Maple Leaf coins from 2014 and onward do have a small laser engraved maple leaf security mark with specific year inside the leaf. This mark may look like a privy but it isn't and therefore it's not a marketing gimmick....it serves a specific security function.


I see in a couple of your other videos you are a collector of the ATB 5 oz silver coins. I really like this series too.....the US Mint's first 5 oz silver coins.




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The last coin in Canadian Wild life series is beautiful. I have some coins of previous years - birds of pray and others. Some of them have spots and some not. So it is totally depends on your luck. And I'm not always lucky :(
P.S. Yes, I love 5 oz US Mint American Beauties! I post a series of videos in my channel about them. Like to post additional information not only about coins themselves but also about national parks of USA.
 
mmissinglink said:
kutylin, that's some serious milking on the Queen in the video.

I thought I was never going to buy another RCM bullion coin again but then I saw the 2016 Cougar and well....it's a beautifully designed coin. So I purchased some high graded ones. The 2016 Cougar coins are completely spot free. I have sealed them in plastic now and put them in my SDB. In a few years time I will take them out to check if they are still spot-free.


I have never bought into the marketing gimmick of the privy marks. I don't own any 'exclusive' privy mark coins and I never will buy any. Now of course the Silver Canadian Maple Leaf coins from 2014 and onward do have a small laser engraved maple leaf security mark with specific year inside the leaf. This mark may look like a privy but it isn't and therefore it's not a marketing gimmick....it serves a specific security function.


I see in a couple of your other videos you are a collector of the ATB 5 oz silver coins. I really like this series too.....the US Mint's first 5 oz silver coins.




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:lol: milk free spot free

Of course they are Free!!!

Don't need a few years to wait
 
You are right. The Canadina privy horse shown coin in my video didn't have milk spots 2 years ago. And now... And it was held in airtite capsule.
 
Airtites are not air tight. Very shortly after I purchase my Canadian silver coins, I seal them up in plastic bags after expelling as much air as I humanly can (without a vacuum sealer) hoping that this will stave off the milk. Only time will tell.



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mmissinglink said:
Seems as if the mints don't care so long as they can sell the coins.

If only collectively we could boycott the products that have the most milking issues to a point where it affects the mint's bottom line......but I doubt that will happen.



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They do cares!!!

Check out their new finishes
 
Golden ChipMunk said:
mmissinglink said:
Seems as if the mints don't care so long as they can sell the coins.

If only collectively we could boycott the products that have the most milking issues to a point where it affects the mint's bottom line......but I doubt that will happen.



.
Click to expand...

They do cares!!!

Check out their new finishes
Click to expand...



I must be slow because I have no clue what you mean. Which new finishes?




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