Searched an amazingly fun and varied box of customer rolls... There were a lot of toned coins in the search. I'm guessing someone had the rolls stored for quite a while as the types of toning varied by roll. There is nothing suspicious from what I can tell by the variety of coins and toning, looks like all natural toning to me. During the search...a couple rolls of dimes, one roll of quarters, and one roll of nickels had this very blue toning. It's not hazy, it's like antique iridescent glass with all the coin's luster showing though. It's really pretty.
Interesting. Can you post a couple of photos of the blue coins next to normal white ones? It's always hard to judge color from photos without a reference. Lots of copper and nickel compounds are bright or deep blue, and there are ammonia complexes that are even more strongly colored. If you have lots of these and wouldn't mind sacrificing one or two, it would be interesting to dip one briefly in white vinegar (then rinse promptly) and see if the color disappears immediately. Actually, before even trying that, try soaking one in water and see if it comes off. Or if you want to keep them the way they are, that's probably even better.
I too wonder about intense blue. I have 30 of these 1982 Norwegian 100 Kroner in .925 Silver. 800,000 struck. They have always been kept together in the same box and in the same place. They all have pastel toning on the reverse but this one is the only toned obverse.
The coin is made of metal so when you add in oxygen and sulfur it will react to the metal resulting in a blue color. The toning process can be accelerated by heat, moisture, and various chemicals in the environment. Some of the most harmful chemicals to coins can be found in cheap coin holders and coin folders.
I've seen coins pick up colors in photos when they are photographed with the colors close by. Are the blue colors visible prior to photographing?
Whatever environmental factors caused the toning in the first place? I think that's pretty close. We've nickels and dimes like these, too. They're breathtaking when they're in high grade. The others, ah, they're blue. And some, like here, are really blue. We don't have any that are really, really blue, or really, really, really blue.
What color was the wrappers? Like Eddie said environment could cause such...if those are indeed the wrappers they been around since the late 60's depending on chemicals in the paper,inks, where they were stored. I had 3 rolls of IHC a lady found in her garage her late husband had place out there. Each cent was eaten....not like bites but layers of copper dust came from the rolls...and the devices on the coins were evenly worn or eaten by what ever caused the reaction. They were dusty and smooth once you wiped the dust off. These may of been stored in a warm environment or in a moisted who knows...what we do know is something happen from the time the owner rolled up the coins and you opened the rolls.
MS70 will and does create blue tones on most coins. Usually more on copper than cupronickel. I find quite a few blue tones on new MS condition cupronickel coins. They can't all be treated with a product. This was one of the more recent finds here in the Mile high with some deep blue tones. This Proof cent was treated with MS70.
So I've been busy with work but I'm paying attention I pulled out one of the other blue dimes I didn't originally post and gave it an overnight (about 16 hours total) acetone bath. It wasn't photographed under the exact same (time of day) lighting and here you go...Things changed...Discuss BEFORE ACETONE AFTER ACETONE OVERNIGHT Should I now follow with a Xylenes bath for fun. Yes, yes I will Sorry, forgot to do that...center of the coin after acetone bath is a good reference. But I'll pull out another one of these blue dimes and give a water soak to see if anything happens as well. Well, my degree is actually in commercial photography lol...so I'm going to say "that's 100% not it". The rolls before I opened them are posted above in my original post
