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 Replies: 58 / Views: 4,674 |
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Pillar of the Community
United States
1203 Posts |
Guest Commentary in July 4 issue of Coin World by Weimar White. A chemist for 42 years and specialist in Carson City coinage and member of the LIberty Seated Collectors Club, American Numismatic Association, and American Chemical Society. Here are a few of the statements made by Mr. White; quote:
It is a fact that whether a coin is lightly or heavily toned, the metals in the coin have experienced oxidation, which is the loss of electrons resulting in chemical wear.
I take this to mean a toned coin has been damaged to some degree. quote:
When a silver quarter dollar is toned golden on both sides, 260 micrograms of silver have been removed from the the atomic state. Toned red it would have lost 440 micrograms and if it were toned blue, it would have lost 700 micrograms of silver by oxidation. The darker the toning is on a silver coin, the more metal oxidation has occurred, which etches away the cartwheel spin or mint luster. Blue or black toning cause the most damage to the radial corrugations on Uncirculated coins.
This don’t sound good to me! quote:
Frequently, when a thiourea dip is used to remove the black or blue toning, the dip is blamed for the dullness of the MInt luster, when in reality it was the toning that etched the surface of the coin through oxidation.
This is what I’ve always been told. Now I find out its the oxidation! quote:
This is easy to prove by weighing a toned silver coin to the nearest 0.1 milligram and then dipping it in a thiourea solution. Rinse the coin in water, dry it and weigh it again. Record the weight loss. Then dip the coin again and rinse , dry and re-weigh it again. You will see that virtually all the weight loss occurred in the first dipping, which means that only the oxidized metal was removed.
Maybe there is something to this after all. Mr. White finishes with this statement; quote:
I have suggested that toned coins not be designated as “Mint State”, because they were not toned when originally minted.
After all this I still like those “honey” colored Buffalo nickels, but then they aren’t silver are they. |
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Pillar of the Community
Belgium
2078 Posts |
If you want the silver to have its electrons back  put it on old aluminium poor hot salted water over it  The silver whatever will return to the silver state The tone which is lost is due to the fact that the newly reformed silver has not the density of the original silver But with this method you do not soak away a layer but reconverte what was lost |
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Valued Member
United States
421 Posts |
Quite interesting! I do have a little heartburn with his statement quote:
quote:
I have suggested that toned coins not be designated as “Mint State”, because they were not toned when originally minted.
...or at least the reasoning. One could easily say same thing about bagmarks. They were not bag marked when they were originally minted. If one starts using that kind of definition for 'Mint State', one will soon find out there are few, if any Mint State coins out there.  Edited by Stujoe
07/01/2005 2:26 pm
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Pillar of the Community
United States
7123 Posts |
Can anyone convert the 260 micrograms to an understandable weight ?some times these scientific types get so full of their selves that they forget they are talking to mostly regular people !! who dont have molecular scales available to them !! I mean really he's talking atomic state here !!!
Rick
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Valued Member
United States
57 Posts |
I'm sorry..I though Mint State referred to the amount of wear attributed to circualtion.....
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New Member
United States
41 Posts |
My understanding of the Mint State designation was that it was to account for a coin that came out perfect (or as near as possible) and the numbers from 70 on down were to account for the normal wear and tear (bag marks, circulations rubs, etc) that the coin went through. Toning, while I agree occurred when coins were placed in Whitman (or the like) folders, was not a normal (Abnormal?) part of the circulation process. And artificial toning is beyond anything that would happen to a coin. In addition, since it does erode the surface of the coin, I consider it to be as similar as the colorization that they are doing to state quaters
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Valued Member
United States
421 Posts |
quote:
Originally posted by Metalman
Can anyone convert the 260 micrograms to an understandable weight?
According to an online converter that I found... 260 micrograms = 0.0000092 of an ounce but that is also so small as to be almost impossible to convert to an understandable weight. I would call it splitting hairs if not atoms. |
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Valued Member
United States
421 Posts |
Well maybe this...a one oz silver round that lost .0000092 ounces of its silver to toning would have decreased 0.00644 of a cent in value at a spot price of $7 an ounce.
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Pillar of the Community
United States
7123 Posts |
Stu
Thats what I thought, someone making a big deal out of nothing with terms that are not easily converted.
Rick
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Pillar of the Community
 United States
1203 Posts |
If you will go back and check, you will find this isn't a one ounce silver round, but a silver quarter that these measurements are taken from.
As for myself, it isn't the amount of silver lost that matters, as much as the reason the coin changes appearance when dipped. It seems to matter very little what type of wash is used, its the silver extracted as converted mass that counts.
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Pillar of the Community
United States
7123 Posts |
OldDan
If you say so !! but what if the coin is not washed, it appears from the the test given that it is only with dipping and cleaning away the oxidation that any mass is lost ? the same could be said of abrasive cleaning , or natural wear on the coin.
I believe that it is a scientific attempt to cause toned coins to no longer be accepted and gradedable as mint state coins , nothing more nothing less !!
Rick
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Valued Member
United States
218 Posts |
Old Dan it looks like you've accosted Metalman's sacred cow!
Metalman, the important point here is that that weight (that can be removed by dipping) is not silver weight, but instead is Silver Sulfide (the most common form of toning on silver coins). The point is that the dip is removing NO silver at all, but it is removing the Ag2S which has already eaten the luster off of the coin. Thus the "overdipping" effect is really just a result of normal dipping when the toning has built up for too long or when the toning is removed and comes back and is removed again, too many times. The overdipping damage is not from the dip per se, it is really an accumulation of damage from too much toning.
Remember that cartwheel luster comes from the fact that a coins surface has flowlines in it from the striking pressure. the surface of a new coin (under magnification) looks something like: /\/\/\/\/\/\/\/\/\/\/\/\/\/\ but after it has toned, the surface begins to smooth out as the toning eats away at the peaks of the flowline ridges, converting the peaks into plateaus and once the toning is removed the coin won't have the same luster since the flowlines won't be as pronounced.
That said, so what! If you like toning collect toned coins!! It's that simple!
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Rest in Peace
United States
2884 Posts |
I ghink it has been determined that a toned coin has been damaged. Just as bag marks, nicks and other damages move it away from perfect mint state, toning should move it down the scale as well. Pristine, mint state coins cannot be toned and appear just as they did when they were produced. This is not an issue of whether you like them or not, just merely what their state of preservation is. Mike |
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Pillar of the Community
United States
1203 Posts |
Metalman...If you like toned coins then by all means buy them for your collection. I have no desire or intention of impuning anybodys sacred cow.
I would however admit that both Cave Troll and Mike hava taken the information as intended as I hope you will.
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Pillar of the Community
Australia
1091 Posts |
My thoughts...
The toning of silver caused by oxidation could be considered rust.
The reason a metal rusts is because of it's exposure to air.
Placing a coin in a 2x2 holder, having it slabbed or placing them in a sealed microwave safe plastic bag will keep the coin away from the atmosphere.
This should reduce or prevent the toning in the first place.
Why a "microwave safe" bag? Some plastic bags give off their own vapours and react with metals and therefore are not a good choice.
I found the information interesting concerning the effect and weight loss of dipping and removing the oxidation.
What is a thiourea dip?
I have heard of Ageka's method of restoring the silver with the use of aluminium foil and
hot salted water but have never tried it. This may reduce the weight loss but what does the coin look like afterward?
As Cave troll suggested that under a microscope the surface may smooth out as it's toning, I don't think any method of cleaning would restore that.
BTW, to the novice collector...
Rule number one: Don't clean coins.
Rule number two: When you do, don't try it with any coin of value.
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Pillar of the Community
United States
7123 Posts |
quote:
Originally posted by The_Cave_Troll
Old Dan it looks like you've accosted Metalman's sacred cow!
Metalman, the important point here is that that weight (that can be removed by dipping) is not silver weight, but instead is Silver Sulfide (the most common form of toning on silver coins). The point is that the dip is removing NO silver at all, but it is removing the Ag2S which has already eaten the luster off of the coin. Thus the "overdipping" effect is really just a result of normal dipping when the toning has built up for too long or when the toning is removed and comes back and is removed again, too many times. The overdipping damage is not from the dip per se, it is really an accumulation of damage from too much toning.
Remember that cartwheel luster comes from the fact that a coins surface has flowlines in it from the striking pressure. the surface of a new coin (under magnification) looks something like: /\/\/\/\/\/\/\/\/\/\/\/\/\/\ but after it has toned, the surface begins to smooth out as the toning eats away at the peaks of the flowline ridges, converting the peaks into plateaus and once the toning is removed the coin won't have the same luster since the flowlines won't be as pronounced.
That said, so what! If you like toning collect toned coins!! It's that simple!
I dont have a sacred cow !! LOL Thats a good explaination cave Troll all I'mtrying to say is that I dont consider toning to be the same as wear! and that toned coins should continue to be graded in the Mint state just as all other coins,( I'mspeaking of NT coins here , I'mnot a fan of treating coins to achieve toning ) based on Old dans original post , the gest of it was weight removed with numbers given to prove the amount, Now I agree that luster is a factor in grading coins, just as nicks dings and wear, obviously a toned coin will not have the same cartwheel effect as one that is blast white, but the detail remains and it would appear that the TPG's also feel that they can be graded as mint state coins. This leaves only one reason IMHO for someone to go after that aspect of toned coins and that is to eliminate them from the count to make their coins to more Rare or less coins achieveing the grade thus increasing the value By the way,I own at the most three nicely colored toned coins,I dont collect them with any intention! Rick PS Mike ? damaged ? no coin goes unscathed by the environment!! where would the line be drawn ? Edited by Metalman
07/01/2005 9:42 pm
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Replies: 58 / Views: 4,674 |
Posted 07/01/2005 2:25 pm
