Exclusive to silverstackers electron microscope images of white spot

Discussion in 'Silver Coins' started by bron suchecki, Jan 7, 2015.

  1. Vezpit

    Vezpit Member

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    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.
     
  2. bron suchecki

    bron suchecki New Member Silver Stacker

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    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.
     
  3. mmissinglink

    mmissinglink Active Member

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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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  4. bloggie

    bloggie New Member

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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.
     
  5. hiho

    hiho Active Member Silver Stacker

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    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?

    [​IMG]
    Source:
     
  6. SpacePete

    SpacePete Well-Known Member Silver Stacker

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    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

    [​IMG]

    [​IMG]


    From another forum:

     
  7. Guest

    Guest Guest

    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.
     
  8. Mintaka

    Mintaka Active Member

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    I have moved back to bars rather than buy coins. Dealer did not advise me of white spot problem. Not impressed.
     
  9. kutylin

    kutylin Active Member

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    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
     
  10. kutylin

    kutylin Active Member

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  11. mmissinglink

    mmissinglink Active Member

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    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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  12. kutylin

    kutylin Active Member

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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]
     
  13. mmissinglink

    mmissinglink Active Member

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    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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  14. kutylin

    kutylin Active Member

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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.
     
  15. Golden ChipMunk

    Golden ChipMunk Active Member

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    :lol: milk free spot free

    Of course they are Free!!!

    Don't need a few years to wait
     
  16. kutylin

    kutylin Active Member

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    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.
     
  17. mmissinglink

    mmissinglink Active Member

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    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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  18. kutylin

    kutylin Active Member

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    Good decision! Let's talk about results in 2 years!
     
  19. Golden ChipMunk

    Golden ChipMunk Active Member

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    They do cares!!!

    Check out their new finishes
     
  20. mmissinglink

    mmissinglink Active Member

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




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