What causes BLUE toning on coins & why is it so uncommon?

Colorfulcoins

I happen to like coins with vivid Blue toning and finding coins with that toning is a challenge (of course, that makes it kind of fun also). I've found that silver Rosy dimes (1946-1964) seem to be the most common coins to find in blue and specific coins such as 46S, 47S, 50-52PD, 56-64 P mint coins are "relatively" common while I've almost never seen a D mint (other than 58D). Likewise, I've seen and owned several Blue Franklins that are 1958 P or D. As far as quarters, its again generally 1955-1958 coins which leads me to believe its a mint set result. And finally, some 40s Mercury coins are also available.

So what causes Blue toning (more or less just Blue alone not a blue rim on an otherwise colorfully toned coin)? Your thoughts please?

Here's just a few samples......

MoneyLA

On the other hand I have a lot of proof washingtons with vivid blues. What I would like is more vivid reds. cheers, alan mendelson

DCAMFranklin

If you like blue Morgans, then take a look this one

Blue Morgan

rd5425

I don't know what causes blue toning on rosies but here is a cool one I just picked up.

Fairlaneman

I had a dealer once tell me that green was one of the first colors when a coin starts toneing and that is why you see very few greens. Just wonder if Blue is right behind green in the toneing process. Yellow is tough to find also. Light pastel blue is one I look for. Have only seen a handful of Mercs with this color.



Ken

Casey

Craig, your 47-S is incredible. I've never seen such a vivid blue. Wow.

CarlWohlforth

Do blue coins come from blue Whitman folders?

Elcontador

You will see some blue toning on Unc. Buffalo nickels (I have a 38 D in 6 with golden rims & blue
centers) & on Unc. or Proof Liberty Nickels if you see enough of them.

Re the latter, it could be the chemicals in the tissue in which they were packaged by the mint.
Re the former, it relates to chemicals in the albums in which they were stored.

FC57Coins

Contador - they're gorgeous! - Blue is somewhat unusual to see on coins - but it's great when you do - my guess is that it's one of the colors that silver turns when it's exposed to sulfur.

Frank