What´s your view on silver coins turned black? I´ve heard coin dealers say “blackening” of silver coins do not lower their value. I don´t understand how this is possible. To me a black silver coin is a damaged coin. The coin is no longer silver, it´s silver oxide. A sad example is my 1818 british Crown (scan):
Because if left black it's unaltered. If cleaned it's damaged forever and worth little if anything. Guy~
Minor point. The black is more likely silver sulfide than silver oxide. And the coin is no more damaged than all these rainbow toned coins.
It can be dipped in a mild solution without damaging it, as long as you don't do it too much/too long.
Disagree 100%. Once the toning turns black the very next step is irreversible and unavoidable corrosion for then the toning will virtually eat the metal. You never want to allow your silver coins to tone to the point that they turn black. This coin specifically though - is not black. Yes the toning is quite dark, but it has not progressed to the point - yet - of damaging the coin. You just need to ensure that it does not progress to that point. You can do this with proper storage. And any dealer that says - " “blackening” of silver coins do not lower their value." - should be avoided like the black plague. For either they don't know what they are talking about, or they are trying to sell you damaged goods.
As usual GDJMSP is correct with that explanation. Since so many items we eat with today are now Stainless Steel, many have forgotten the good old days when Silverware was really Silverware. And how our Moms had to constantly clean them with special fluids like Tarn-X. This removed the darkening but the darkening was in reality part of the Silver. In normal air with the correct gasses present, Silver will combine with many of them readily forming different discolorations. Naturally the most common are AgNO3, AgF2 and Ag(S)5)3. The problem with Silver is this process continues until all the Silver has been Compounded so anyone that says it does not lower the value is sort of a little wrong.
I doubt that. The darker the toning the more silver from the surface has been chemically altered. By the time it gets this dark the surface is etched under the toning.
The coin seems to be on the point of if something is not done, will eventually create irreversible damage. If it is acceptable to you in the current state, I agree with GD ( Doug) that containment storage should hold it in that condition for a long time. I personally ( and there may be disagreement) would do a quick rinse with acetone to remove any unseen organic material which might be a foci for corrosion, and then put into a holder of your choice that claims to inhibit corrosion. If it is not acceptable, you could either try to sell before it gets worse, or attempt a time/dilution dip with a solution to lighten it. The color is due to the depth of the sulfides or other chemical combinations , and by lessening the layer, the color will be lighter, but may be splotched or a coloring you won't like. A 1:5 or a 1:10 dilution of the dip solution with water will slow the reaction down significantly and allow you to observe the coloring along the way. Removing and rinsing when just a little darker than you want. You can always repeat if you determine it is still too dark. You have less chance of going the other direction. Now this means you have to be happy with the idea that it may fail what you want. Any artificial de-toning or toning is often unpredictable in outcome. By removing just some of the dark tone, might misrepresent the surfaces as being less damaged than they actually are. If you intend to keep the coin, this is not a problem. But if you do any chemical change, take photos! Jim
