Clouding on Proof Silver Coins

Discussion in 'Coin Chat' started by JCro57, Feb 3, 2018.

  1. GDJMSP

    GDJMSP Numismatist Moderator

    I think it was in one of the first posts I made in this thread but I mentioned that the Ikes were a different alloy than the Morgans - that 80% silver vs the 90% silver is what I was talking about. But there's even more to it than that.

    Think of modern Proofs, you have both clad and silver, and the silver in them is 90% silver, just like the Morgans. However, both versions (clad and silver) of the modern Proofs develop haze while their business strike brethren (also clad) do not.

    My point is this, there's a whole lot to think about when you are talking about this subject - lots and lots of little details. And all those details, I prefer to call them variables, are what explains the differences in how the coins tone and or don't tone. Even when you have all the similarities thrown into the mix as well.
     
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  3. 2011steeny

    2011steeny Member

    No, I'm not saying that any or all of the other factors do not play a part in the coins condition. My post was based on the current synopsis of the original posters question, concerning the hazing condition of the coins surface.

    In each case, and coin scenario, there will always be differentiating causes and effects on the coin in question. The reply I gave was simply based on my, past, previous, experience of more than 35 years of coin collecting.

    I do appreciate your reply though, it was a very good question, and the items covered will all have certain effects on coins.

    Thanks
     
  4. desertgem

    desertgem Senior Errer Collecktor

    Hmm, I haven't thought of making high power photos of silver , clad Modern proofs ( both) and clad business strikes 100 and 400X like I once did with Morgans and Peace. I will have to watch for cloudy proofs as I do not think I have any other than cents. Jim
     
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  5. 2011steeny

    2011steeny Member

    Thanks for the comment. Any significant cloudy/hazy surfaces on proof coins Should, be clearly visible with the naked eye. Some of the older proof coins, (pre 1968), may need to get a closer look, but the newer S minted (cameo/ultra cameo), versions should be pretty visible.

    Thanks for the comment.
     
  6. Nathan401

    Nathan401 Quis custodiet ipsos custodes?

    What was the difference, if any, with the Peace and Morgans under that magnification?
     
  7. desertgem

    desertgem Senior Errer Collecktor

  8. Searcher64

    Searcher64 Member

    Have you ever tried a solution of hot water, in a glass bowl, with a tea spoon of baking soda, a small piece of aluminum foil after ruffing it up with sand paper. Next, place the silver coin in just touching he foil and watch. remove as you see the desired results. Then dry the coin, with out rubbing, just patting or blow dry at a safe distance. Let us know if and how it turns out if you do.
     
  9. -jeffB

    -jeffB Greshams LEO Supporter

    (Assuming you meant "grating" there...)

    I don't think that can be right. If it were, you'd always see a rainbow that shifts as you change the angle between the coin, the light and your eye, right?

    Flow ridges make luster, which does not have a color component -- it reflects white light as white light -- so I don't think those ridges are acting as a diffraction element.

    As for the color of toning, isn't it pretty well-established that that's an interference effect, dependent on the toning layer's thickness, and that's why the colors you see stay in one place instead of shifting across the coin as you move it?
     
  10. desertgem

    desertgem Senior Errer Collecktor

    Jeff I have read sunnywood's posts as well, and I do think I left a lot of meat between the skin and the bone and I apologize. I didn't mention the interference of the two surfaces to produce the coloration seen and I agree with his hypothesis, but it doesn't explain why the Peace dollar toning typically is much flatter in visual appearance than the toning on a Morgan even exposed to the same environment and that was what I was trying to explain. On the coin flow lines? ( what else to call them) all of the inclined (side)surfaces have the film interference as well as any microscopic base areas, so my thought is that since they are probably of different angles and altitudes on the surface, the light ( color) from a relatively smoother surface would allow the color to stay more coherent than the color from the more incoherent Morgan surface with higher semi-random ridges on the surface. We are seeing the tone with our eyes/brain which throws in a wild card as to how the brain uses the variations to see a color as flat or as sparkling ( flat paint/glossy paint) even though the same wavelength of light interference (color wise) is there, the base matrix of the paint of course causes most of that, I suspect. Sorry for the rambling. Jim
     
  11. -jeffB

    -jeffB Greshams LEO Supporter

    Yeah, rambling is my job. ;)

    I do think it would be possible to get to the bottom of this, or at least expose a lot of bedrock, with the proper knowledge and equipment. Unfortunately, I'm not there on either front. Doesn't stop me from being enthusiastic about it, though...
     
  12. GDJMSP

    GDJMSP Numismatist Moderator

    What Jim is pointing out here is that it is the huge differences in the type of luster each coin has that produce the appearance each coin has, toned or not toned, as well as why Morgans are far more prone to toning than Peace dollars are. More flow lines, that are higher and more closely spaced, equals being more prone to toning because more area of the fragile luster is exposed to the air.

    No, not necessarily. If the coin is not toned you will see white, if the coin is toned you will see color.

    Yes it does. But, once those ridges tone, there is a color component.

    I agree, he used the wrong word for this instance. It's not diffraction, it's a combination of refraction and reflection.
     
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