Firstly I want to be clear: None of this is about or related to “monster toning” or artificial toning of any kind. Only natural toning not done deliberately. Here is an example of a toned Morgan Dollar. I’m wondering how long it takes for toning on a coin like this to be noticeable to the naked eye? Because I imagine someone doesn’t just wake up one day and find a rainbow toned Morgan when the day before it was blast white. I’m assuming it takes time for the colors to develop. Oh and what causes them to all tone uniquely with different colors? I have old coins but they just seem to tone darker and darker with patina. But they don’t change colors. Is it chemicals in the air? Humidity? Or some other environmental factor? Or just an Act of God no one can explain?
The length of time to tone depends on the method and environment. Many of the toned Morgans you see today sat in bags for many decades before they toned (due to the environment and the sulfur-applied to the bags to prevent rats from ripping them open). Other coins have sat in albums, special tissue paper (that is how some proofs were stored in the early days), or velvet trays (collectors kept some coins in cabinets as one method of storage). Then you have accelerated toning (some blatantly artificial and some that replicated natural conditions but speeds it up). This can be done anywhere between a few minutes to a few months. As far as environment-that matters too. If the coins are in a humid or hot environment, they could tone quicker than in a cool environment (where they may not tone at all).
There used to be a good website that talked about toned Morgans but it seems to no longer be active. Another person has created a similar website and it has plenty of good information. Take a look here: https://www.monstertonedmorgans.com/all-about-toned-morgans
Thanks I finished reading it. That definitely answered a lot of questions. I was hoping there was some way to squirrel away some of my coins for 100 years so they would tone beautifully xD
Yes, usually not , but the coin surface itself is most important. this is the surface of a Unc. Morgan x400 with a lab microscope, not USB type. If we could see this cross-surface it would be like inverted VVVVVVV V's. Chemical deposits on the sides interact with the light being refracted back. The wavelengths of the refracted light rays determine the color that the eye sees. Over time, the reacting layers can thicken and the color gets deeper until final "black". With a nice toned MS Morgan the colors when the coin is rotated can vary . If the coin is worn down, the refraction interaction is less and less, until no real toning other than dark occurs. For comparison here is a photo comparing the Morgan MS with a Peace MS at 100X, Morgan on Left , Peace on right . Notice the Peace doesn't have the ridges that we see on a Morgan, so any natural toning will not be as colorful or sharp as on the Morgan. Hope it helps, Jim
I suspect age itself is not generally enough to produce toning. I collect many world (silver) coins older than a typical Morgan, and they almost have any colorful toning at all. I assume certain storage environments are necessary to get noticeable toning even if you wait 100 years.
Yeah same here. I even have some AU ancient Roman coins and only 1 of them is toned. My Hadrian denarius. The rest are just silver colored.
Taco Bell napkin in the window sill experiment still remains the best example, to me. I assume some here have been around long enough and on other coin related sites, to recall this.
Blake as you've been told by the others literally everything matters and everything contributes to toning. And that everything includes the coin itself, which is what Jim was pointing out. But it even goes a little bit further than that when it comes to the coin itself. This is because toning is dependent on luster, and not just luster but the quality of the luster, the degree of the luster. Pretty much everybody knows that when coins are struck this one or that one will have a better quality of luster than another one. But what they don't realize is that higher quality, and conversely lower quality, of luster also makes a difference when it comes to toning. And, so does the type of luster. And I say type of luster because each every coin type, has its own unique type of luster. And each type of luster tones differently. That's how those high magnification pics of luster came to be, it was because the first time I pointed this out years ago another member took high magnification pictures of a bunch of different coins to see if I was correct or not. The result was, well you can see for yourself. As for your question of when does toning become noticeable ? That largely depends on how well trained your eye is. As I've said many times, toning begins the instant a coin is struck. So if your eye is well trained, and depending on conditions of course, you could possibly see toning differences in as little as a couple of weeks or a month. Other times it may take a few months. But it is an absolute fact that toning of one degree or another has occurred within those first few weeks. And this of course is referring to natural toning, which is what you specified. That said, toning like that on the Morgan dollar you pictured, that can be duplicated in as little as few hours. And it can be done using the exact same things that caused the toning to occur naturally. This is because natural toning occurs because of the gasses in the air. Take those very same gasses, concentrate them in a confined area, and the toning will literally occur right before your eyes - as you watch. And if it was done, absolutely nobody could ever tell it was done.
It is mostly the result of oxygen and/or sulfur reacting with the coin's metal. Silver does not readily react with elements in normal air (Nitrogen 79%, Oxygen 20%, remainder trace Carbon Dioxide, Argon, etc.), at normal temperatures, but the metal will oxidize at high temperatures and moist/humid environments. Most common is Silver Sulfide (Ag2S) as the type of toning that affects coin collections. it is usually sulfur and halide containing compounds that make silver tone the various colors sometimes and seen as brown or black. Silver Sulfide as a compound is a dense black solid, it is the only sulfide of silver. It is useful as a photosensitizer in photography. It's the tarnish that forms over time on silver. there's also Silver halides, Silver Bromide (AgBr), Silver Chloride (AgCl),Silver Iodide (AgI), much less common to be the cause though. All of this happens on the molecular level, electrons from the contaminant, joining with the elemental silver, Silver is a metallic element that loses one electron to become a positively charged ion, Ag+1. The sulfur atom needs two electrons to fill its valence electron shell. A valence electron shell is the outermost part of an atom's electron cloud. When a sulfur atom gains two electrons, it becomes a negatively charged ion, S+2. Sulfur can get these two electrons from two silver atoms. After this transfer of electrons occurs, the two ions stick together forming an ionic compound, Ag2 S Visually, this process terminates as a coin with a flat black appearance that light cant' pass though the layer of Silver sulfide. As the layer of silver sulfide is formed on the surface of the coin, it gradually thickens. Different thicknesses produce the appearance of different colors. The colors are caused by "thin film interference". rather than explain it, link to wikipedia: https://en.wikipedia.org/wiki/Thin-film_interference the surface of the coin matters, because it is reflection of light that makes it all possible, but as far as the colors that become visible due to the thickness of the silver sulfide film, it's due to the film on the coin it's thickness and the optical path length difference for light reflected from the upper and lower boundaries of the thin film. similar to a rainbow in a soapbubble, or a rainbow in the sky, "thin film interference" with the light waves. The gist is that light reflects off the surface of coin at a certain angle, as the silver sulfide thickens, the light bends between the upper and lower layer of the film reflects off the surface, and bends again and produces a color for that wavelength of light. Now, color isn't "real", an apple isn't "red", the sky isn't "blue", a color blind person isn't going to interpret colors the same way as a person that isn't color blind, or the the fine sighted, and the sight impaired might see color differently also. without light, there is no color, and color is our interpretation of what we see, the eyes (sensors) feed the data to our brain (computer) that translates the image. Colors don't really exist either, it's what out eyes pick up and our brains translate to color, and for the most part everyone's works the same, but there are malfunctions and defects, which in all truth, might just as well be the correct way the world looks, (the color blind) while the majority have this "color sight" as an advantage to identify hot from cold, or dangerous or not, or food from rock, ect. NOW, I am not a scientist, or physicist, or a chemist, just an interested hobbyist that reads a lot. So I've got a basic understanding, not a firm grasp on any of these concepts and I can be wrong on it in some areas, although I feel I've got a decent understanding of it. As far as the "rainbow toned morgan dollars" a whole lot of them were stored in vaults in canvas bags for long periods of time. There's a theory the canvas bags were treated with sulfur as I understand it ( and sulfur was used as a repellent and even a pesticide in the paper industry so I think this is plausible) , to deter rats from chewing the bags and dumping them all over the vault floors. In many cases, this did happen "overnight" as far as the people and the coin were concerned, they were put up and forgotten, and years later someone opened the vaults and the bags and the coins were colored up, whether over night, or over a decade or 20 or 30 years, who knows. it's a Schrödinger's cat kind of thing, who knows until you look and know, and then you know. it could have been an event over a short period of high heat or cold and humidity that settled in the vault, and then retreated, but that day or week or month of it, did the coloring up and then the humidity retreated. There's a lot of factors at play and it's all been explained if you care to read the science of it all. it could be that Morgan dollars weren't really used all that much when they existed, and they sat in canvas bags, and sat and sat. it could be the surface of the coin as struck at the time, it could be environmental factors, and it is likely a combination of it all at play here as to why "rainbow toned" Morgan dollars are much more common than peace dollars, or trade dollars flowing hair, draped bust, ect. toning can take centuries to develop and eventually turn flat black, and it could take seconds if you took a coin and stuck it in a container of sulfur. it depends on the conditions of the environment, temp, humidity, contaminant availability, ect. if you are familiar with Nitrofil for car tires, I am sure if you put a coin in a vessel and pumped it full of pure nitrogen, there would be no oxygen, or sulfur and so no forming of a layer of silver oxide or silver sulfide. as long as the vessel remained sealed and filled with nitrogen, the coin could sit as fresh as the day it was minted with no toning whatsoever for 1000 years or more. As far as coins that just tone dark, older coins, it's posible they don't have much surface reflection to begin with or have been worn down or cleaned and the surface damaged to where it's not reflecting light, in which case you won't get color, you'd just get blackening, silverware is a lot like this, it tarnishes dark, and requires polishing to make it bright again, but will again tarnish darkly. it doesn't have the right surface to maintain a luster that reflects light at the correct wavelength to produce colors from the silver sulfide film, if a coin has toned terminally, to a grey or black, dark color where light no longer passes through, enough surface of the coin silver has been sacrificed to silver sulfide that it may impair the luster of the coin forever, and it will never reflect a rainbow or colors as it once did.
On this topic/thread and getting back to the Lincoln Boyhood Cents as related, I have two sets of the four different 2009 copper pennies (8 total)...each in its own 2x2 stapled, white cardboard holder for 11-12 years...in addition to two sets of 4 in the OGP plastic case/holders...ALL stored in the same cool/dry place with no other known influence of contaminants, etc. Not one of the eight cents in the 2x2 individual cardboard holders is toned even a little...no indication of anything to the naked eye...not spots, not darkening/fading...totally MS/BU as if just off the press. The other eight cents in the OGP holders (two, with four coins each) are toned between moderate and total...not unattractively but certainly obviously...darkening and no longer BU. You'll never convince me this is in any way random or environmental, etc...more to almost an assurance of something...a reaction of one or more components...in/of the OGP/holder. Except that some of the same OGP holders contain pristine cents...totally unaffected. Go figure. Understand it CAN be different and effected by other things mentioned...but not in this instance. It's in/from the OGP holder...or on the coins before holdering...something. For what it's worth.
Short answer to your thread/headline question...and not to be a smart-ass : When you can see it...! If not seen, it's not noticeable.
