Coins are starting to tone… too much too fast?

[Restitutor]

I’ve been noticing for a while now, a number of my coins have begun to tone at what I feel is a rapid pace. I’m a little bit concerned that these coins, many of which came as toneless silver, have turned into rainbows! I hope y’all can calm my nerves that this is totally normal and not to worry, and that toning doesn't actually take nearly as long as I thought it would (I was thinking it took coins decades to tone) because I'm a tad stressed about this at the moment😅

Before (Jul 2022):
Now:

 

Before (Jul 2022):
Now:

 

Before (Jul 2022):
Now:

 

This one isn’t as extreme but if you look closely you’ll see the signs are starting on it in his hair. 

Before (Jul 2022):
Now:
 

And saving the best for last, my most extreme:

Auction House Photo (Sep 2020):
Now:
 

I keep all these coins on an Abafil tray. Blue velvet. They’re “exposed” only in that I don’t cover the tray with anything. House is usually kept around 69°. They do get direct sun light for a few hours a day based off their location in my office, although for all of these coins the obverse and reverse sides are toning at about an equal pace, despite the obverse side being the "visible" side probably 85% of the time. 

Would you be concerned?

[Hrefn]

They are much improved, in my opinion.  

[Limes]

I love the added toning. Actually, would you mind sharing some more details about the way you keep them? It's not just the sunlight, because the back tones as well, so I'm really curious about the secret! Some of my coins are too bright. Not only makes it more difficult for me to photograph them, but I would like them to 'tone up' a bit. 

[Phil Davis]

This rapid toning is surprising for sure, but I don't think you have anything to worry about. I've noticed for a long time now that silver, stored in identical conditions, tones at different rates. Presumably it's a function of the exact composition of the metal. I've had coins change noticeably in just a few years; others are essentially unchanged after decades.

[John Conduitt]

I think they have changed quickly, although I don't think it's enough to worry about. Mine are in capsules in a box and have hardly changed, if at all.

As I understand it, the cause is the air and what's in it - sulphur, oxygen - and accelerated by moisture and heat. So the sunlight will be speeding it up (via warmth), as is keeping them in open trays in a room you're in a lot (via your breath). I don't know how slowly each stage of toning takes - the first layer might only require a very thin film of molecules reacting to defract the light and cause rainbow toning, and once it's there it might protect the coin a bit from toning quite so fast.

Presumably, given they were cleaned anyway, if they tone too much you could just dip them in acetone to get you back to where you started.

Edited May 24, 2023 by John Conduitt

[Curtisimo]

The direct sunlight will absolutely do this in my experience. I’ve noticed that cardboard and some types of paper will do this too (even cardboard coin flips and printed tags) if the coin is on, in or near them for a long time.

Out of curiosity how is the abafil tray displayed in your office? i.e is it inside an oak or maple bookcase or some such? I’ve also noticed that certain types of wood finishes have an effect. I like woodworking so I’ve been experimenting to try and find the least reactive finish (FYI: it’s shellac).

Overall I think the coins still look great with the toning but if they continue to tone at pace you may end up with a deeper black toning. The dark toning is perfectly nice as well in my opinion but it’s worth thinking about whether you have a preference for what is “too much” toning and to plan your storage with that in mind.

[Restitutor]

1 hour ago, Limes said:

I love the added toning. Actually, would you mind sharing some more details about the way you keep them? It's not just the sunlight, because the back tones as well, so I'm really curious about the secret! Some of my coins are too bright. Not only makes it more difficult for me to photograph them, but I would like them to 'tone up' a bit. 

Thanks!! Here’s how they’re displayed:

Pretty simple but it gets the job done. They’re usually kept on my desk and I’ll handle them regularly (had to move them for the moment as I'm redesigning my office layout). They do get a near direct hit from the sun during the afternoon hours based off how my office is oriented. For photography I use my iPhone 14 Pro. I’ll use the RAW setting, 1x zoom, and shine some light on the coins (although admittedly for the “now” photos here I did just a quick shoot vs the usual more involved process I do). 

13 minutes ago, Curtisimo said:

The direct sunlight will absolutely do this in my experience. I’ve noticed that cardboard and some types of paper will do this too (even cardboard coin flips and printed tags) if the coin is on, in or near them for a long time.

Out of curiosity how is the abafil tray displayed in your office? i.e is it inside an oak or maple bookcase or some such? I’ve also noticed that certain types of wood finishes have an effect. I like woodworking so I’ve been experimenting to try and find the least reactive finish (FYI: it’s shellac).

Overall I think the coins still look great with the toning but if they continue to tone at pace you may end up with a deeper black toning. The dark toning is perfectly nice as well in my opinion but it’s worth thinking about whether you have a preference for what is “too much” toning and to plan your storage with that in mind.

Interesting! I'm not exactly sure the wood species of the stand the Abafil tray is on, it's from Alberto Zecchi. I went to his site to check for more info. but looks like he's on vacation and closed down his site for the time being! I'm interested to see what happens to another batch of my coins, I got this for Xmas from Alberto as well and am storing some coins in here (the interior is red velvet). So far no noticeable change in toning, and since they're kept closed not much air gets in, but will be interesting to see:

[Valentinian]

I like the recent toning, but would not want it to go much further. If it continues at that pace some of those silver coins will be black in a few years. I wonder if they are around some source of sulfur--maybe paper tickets than are not archival quality? Local air-pollution? 

[Steppenfool]

Lovely Old Cabinet Tone, and a black rectangle around those should you ever consign them to an auction house. 🤣

Edited May 24, 2023 by Steppenfool

[Restitutor]

1 hour ago, Valentinian said:

I like the recent toning, but would not want it to go much further. If it continues at that pace some of those silver coins will be black in a few years. I wonder if they are around some source of sulfur--maybe paper tickets than are not archival quality? Local air-pollution? 

This is interesting... a quick google search says "Coal mined in the Midwest states of Illinois, Indiana and Ohio have the highest sulfur content of any region of the country". I happen to reside in one of those states. Maybe that is it! I do open the window in my office on a regular basis. Funny to think that pollution could be making my coins look prettier and more valuable, for those of us who prefer a toned coin at least 😄

[sand]

@Restitutor I keep all of my ancient coins in Abafil red velvet 1 compartment trays, which are kept within Abafil "Diplomat 2" cases, 1 tray per case. Occasionally, I'll open the cases, to look at the coins, or to add newly acquired coins, or to photograph coins. I've had multiple shiny silver ancient coins for 2 or 3 years. I haven't noticed much toning of the shiny silver ancient coins. I agree with @John Conduitt, that keeping the Abafil tray in the open air, and in occasional direct sunlight, is probably causing your silver ancient coins to tone more quickly. I wonder if putting UV film, on your office windows, would help at all. I'm guessing probably not.

Perhaps, if you put a glass sheet over the tray, that would decrease the rate of toning. I would recommend a glass sheet, rather than a plastic sheet, because I'm wary of any sort of plastic being near my coins.

I like toned ancient silver coins, even if they are toned black, especially if the toning is somewhat even. My favorite is your 2nd to the last coin, the Hadrian, which has a nice, even, dark gray tone. Some of your coins have toned unevenly, but eventually, perhaps, as they tone further, the tone will become more even.

Edited May 24, 2023 by sand

[Qcumbor]

My guess is sulfur too. I understand the place you live has a high content of sulfur in the air. Add to that some cauliflower and egg cooking not far from where you store your coins and you're done

Nice coins and toning BTW

Q

[CPK]

I like the toning. But you're right, it does seem fast. I think, though, that the first initial toning is more quick to come on, and that the darkening process slows as it progresses.

[Limes]

14 hours ago, Restitutor said:

This is interesting... a quick google search says "Coal mined in the Midwest states of Illinois, Indiana and Ohio have the highest sulfur content of any region of the country". I happen to reside in one of those states. Maybe that is it! I do open the window in my office on a regular basis. Funny to think that pollution could be making my coins look prettier and more valuable, for those of us who prefer a toned coin at least 😄

Since I don't think we'll be moving to any of those states soon, I'd better find a couple of sulfur sticks at the local drug store 😄 

[Edessa]

I live in the deep woods. Closed storage with desiccants and humidity control, although the room is not airtight. I store my coins in the usual inert plastic flips. I occasionally see the edges of some silver coins tone very quickly, as in a few months. Every three to six months I have to take my collection out of the flips and reposition the edges so that the toning eventually becomes uniform around the edges and works toward the middle. It would probably work better if I stored them in trays and just flipped them every so often, but such an arrangement isn't practical in the space that I have. 

Only a very few coins become so unevenly toned that they could be called "ugly". In my experience, these tend to be bright silver coins that have perhaps been harshly chemically cleaned and coins that we know were made of poor or uneven quality silver. 

I tend to buy toned coins, so the problem has not been great. I don't notice coins that have already pleasantly toned continue to tone unevenly or go to black.

[Octavius]

 Firstly, don' panic - your coins are beautifully toned.

I also have kept my coins in Abafil trays and noticed toning on many of my silver denarii after a year or so. That was about 20 to 30 years ago, and they have stayed more or less the same ever since. To me, the toning gives them a richer tone. Given enough time , however,silver will always oxide and blacken. If  you keep your trays in a safe, add a desiccant - you can get them on Amazon. But again, your coins are very handsome.

[robinjojo]

The toning is very attractive, in my opinion.  Really, this is just Nature and Time doing their thing.  In a way the coins are sort of returning to their previous states, generally.  A lot of my ancient silver and bronze/brass coins are dark and crusty, while many are transitioning in color, often kept out to augment the process of toning.   

Now, if you want to stabilize the process somewhat, store the coins in cotton lined inserts in paper envelopes.  I also have some in the old poly-liners (mini bagges).  Those coins have also not changed a whole lot over many years.

[Prieure de Sion]

On 5/24/2023 at 4:16 PM, Restitutor said:

a number of my coins have begun to tone at what I feel is a rapid pace.

... can I send you my over cleaned silver coins for a while? 😂

[Romismatist]

I wouldn't worry either, and agree with everyone that the toning makes the coins look more attractive. Toning rate will depend on the type of silver as well as what it's exposed to. I had some shock white silver medieval coins tone to a rich orangey-yellow around the highlights in about three months, and others that barely changed in the same amount of time. I wouldn't worry... the toning only positively impacts the coin's value, and doesn't imply it is fake (if that's what you were worried about).

[Edessa]

Forgot to add. For a few coins that were toning unevenly, I stuck them in old Spink's paper envelopes. The results have generally been good, with the toning becoming more uniform.

[SteveJBrinkman]

On 5/24/2023 at 8:16 AM, Restitutor said:

They do get direct sun light for a few hours a day based off their location in my office, although for all of these coins the obverse and reverse sides are toning at about an equal pace, despite the obverse side being the "visible" side probably 85% of the time. 

The active component in photographic film is silver.   All things considered there are probably several factors causing the improvements, but given the short timeframe, I would suggest direct sunlight is the major factor.  I've seen modern silver dollars that have been partially toned in a perfect crescent across the face of the coins.  Dark toning in the crescent near and at the edge,  and the other half, bright white.   This toning  has been speculated to be caused by coin shops putting trays of loosely heaped silver dollars  in their front window for display.