Will most rainbow toned coins eventually turn black?

Mint bags back then were impregnated with sulfur to drive away rats. How do you suppose those wild textile toners came about?

The ones on the inside edge of the bag are the ones I'm talking about. The crescent toners, the ones which are wild on one side and not at all on the other (aside the obvious end-roll examples with creased color). For a certain strict definition of "natural," these are the only Natural Toning Morgans, being a direct result of Mint practice. Target toners from albums are postmint features, and what do we think otherwise of postmint changes to a coin?

 

Log in or Sign up to hide this ad.

Good point about post mint, since I would guess 99 percent of toning on coins today was caused post mint. The mint holding silver dollars was an isolated incident.

When it comes to toned coins, I am simply pragmatic. I love original surfaces that promote "natural" toning, I like pretty coins, but I have seen how AT is done WELL, and how any toning can be replicated. So, given that and the ugly fact that toning really IS tarnish, (corrosion), and it will want to progress, I try to buy original surface coins whether they are toned or not. I do not pay a premium for toning.

 

Nicely put. I've been cogitating on it for a while, contemplating the difference between "natural toning" and "market acceptable toning," and coming to a stricter definition of what I consider "natural." The only Morgan toner I own doesn't meet that definition, even though I consider it "pretty."

I think I'd probably pay a premium for one which was both nicely-colored and inarguably bag toning based on the shape of the feature.

But if I did, like the other one, it would go into air-tight storage to hold off the inevitable for as long as possible, certainly as long as I owned it.

 

There is that, and it's a strong argument against a premium for any toner at all.

 

Vacuum has to be the very best way to store coins. Practically no oxygen, hydrogen sulfide, or water vapor. However, the vacuum has to be monitored. The best setup would be a vacuum chamber with a gauge on it or even better, a pressure alarm. Vacuum pump should be an oil-less type. Problem would be getting a setup for a safety deposit box.

It's possible some slabs might blow apart in a vacuum especially if the chamber were evacuated quickly. Maybe a new crack-out method?

I live in a dry climate, so water vapor is not much of a worry. I use Intercept Technology boxes to grab hydrogen sulfide and other metal-reactive gases on their way in toward the coins. The coins are in rigid plastic holders (mostly slabs) rather than paper or cardboard holders. The latter two materials can emit hydrogen sulfide and other nasties. I don't worry too much about oxygen; it's not much of a factor in silver or gold toning; not sure about copper. I've considered putting the Intercept Tech boxes in a bag and flushing the bag with nitrogen or argon, but am too lazy.

Cal

 

This method of storage appears to work ok.

 

All bank bathrooms should have one!

Actually, imbedding in or coating with a clear inert medium might work really well. Ancient and medieval coins were often lacquered as a means of preserving the surface. It worked pretty well, but over the decades and centuries, the lacquer yellowed. There are a number of modern polymers that would last considerably longer, and many could be removed with solvents that would not damage coins. At this point, imbedded or "lacquered" modern coins aren't acceptable to collectors and grading services, so the idea will go nowhere now.

Cal

 

As others have said, they should keep reacting to form the toning till they're black. Things like silver oxide and silver sulfide are more thermodynamically stable than silver, meaning as long as there are the necessary reactants, the silver should keep reacting until the toning has isolated the unreacted silver from the air.

 

Holy Cr*Pper !!
Sorry, that's just a waste of money, it makes no cents.

 

I would think Intercept technology would eliminate that. There may already be 2, 3 or 4 layers preventing air movement plus the slab. If you have a toned coin in an intercept slab cover in an intercept box in a 50% humidity location or less, what's going to get to the coin to continue the toning process? If someone has taken preventative measures, and the coins made it 150 years in the same state with no such preventative measures available, I don't see the concern.

If protected why wouldn't they make it hundreds of years unchanged as they are now? The original source that caused the toning is gone. The argument seems over-blown.

 

On the intercept, when do you know when the sacrificial material lining in the box is fully reacted and any more exposure will result in your coins being the 'sacrificial metal'. I use sacrificial cents ( modern 100% copper shell cents, with abraded surfaces) which can be replaced in any plastic tray or safety box, when they first start to change color rather than wait until my 'real coins' start to turn. And they only cost cents to replace with new ones, and then use to RB coins for change.

 

OK, how about coins you bought when you were a young whippersnapper, they must be over 150 years old...what am I saying, 1,500 years old.

 

Putting a bit of sacrificial metal, usually copper, in a container of coins assumes the reactive gas molecules, like hydrogen sulfide will go the sacrificial metal first. Bad assumption. The Intercept Tech containers completely surround the coins, so the nasty stuff has to contact the sacrificial material first. It's not just a matter of having sacrificial material near the coins, but to also consider geometry so that the sacrificial material gets hit first.

Intercept Tech was developed by Lucent Technology (aka Bell Labs) to protect electronic components. Their patent descriptions can be easily found on the net. It consists of copper particles imbedded in a conductive carbon matrix. That's why the insides of the boxes are black. The effective reactive surface area is huge. Unless you store them in a really bad environment, they'll work for decades. There is no indicator to signal when they are exhausted. However, you can have small Intercept Tech boxes inside a larger one and a piece of copper foil (or pennies if you like) inside the larger but outside the smaller. When the copper starts changing color, replace all the boxes. Chances are you'll never have to do it. I don't bother with an indicator. The coins will outlast me in fine shape in their current boxes.

Cal

 

Nearly all of the non-copper base metal Artex restrikes made in Hungary in the mid 60s were clear coated at the mint before being shipped out to collectors. The TPGs grade them as-is with the coating on them, perhaps because it is original?

 

I would guess you're right. Try coating a Morgan dollar with a clear coat and send it in for grading. Probably would come back in a bag.
Cal

 

Whoa... I would not feel right doing my duty on that... with all of those ladies and presidents and founders ... not to mention bison... watching...

 

Ah, but we DO know that some have made it at least 130 years without a dip because the Battle Creek hoard was slabbed and pedigreed from the source. No dipping. Did some turn black? I don't know but over 10% got a star designation that would indicate they were highly attractive and not black. Not all coins in the same bags did the exact same color pattern. But all the silver faces stayed shiny and new within those bags stored in the harshest of conditions for decades.
Intercept boxes will last for 10 years minimum. They're not being stored in a factory. There's low air movement or exposure to anything unless a smoker is present in the house.
The protection should be over-kill and the change if any would be immeasurable over 100s of years.