1988 Sealed Maple Leaf Toning Question

i have this maple leaf sealed still that has some toning going on the top of the front and back of the coin. Most of the toning is actually on the side of the coin and features some rainbow toning and a robin egg blue color. With this coin being sealed, am I to assume this is intentional toning done by a previous owner, say through sunlight manipulation?

sorry for poor scans, my scanner does not show toning well. Help or hurt value?

 

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I have one from the same year, also sealed, with very similar toning. I'm fairly sure mine was not intentional. My grandpa got it from either the RCM or an authorized purchaser (not sure if they did the AP system)in 1988, and he was not a fan of toning. I say because the toning is not phenomenal, it will neither raise nor lower value

 

you think its worth leaving sealed with the toning?

 

Doesn't look intentional. I got many mint sealed sets with toning developing on some coins and I`d say the reason is exposure of the coin before it was sealed. Environment at the mint might have some chemicals fumes in the air, private homes might have humid conditions or smoke. All these might cause toning to appear few years after the coin was sealed.

What is you other option? Take it out and start cleaning?

 

no i just store most of my stuff in tubes, so this item is kind of seperated

 

Most likely, there is a "leak" in the seal, check around the seal where the toning is most evident. Usually you will find either a very small puncture or separation. The plastic is to protect the surface from abrasion, not necessarily air. This occasionally occurs on almost every type of mint seal, including foreign. But notice it took 23 years for enough air to get in to cause the toning. This small amount of air being sealed with a coin in this type of holder, if intact, can not, IMO and chemical knowledge, carry enough contaminant molecules to cause that amount of toning.

Jim

 

True, but the coin might be exposed for days or weeks or months before it is sealed. This is how the process initially starting and just continues after the coin is sealed. My personal chemical knowledge is quite limited though, just been reading.

I checked few of my mint sets from 1960s from different countries. They show minor toning while the plastic is intact, no punctures.

 

If the coin is sealed from air, the process can't continue. The idea that toning starts unseen and then continues to grow without additional contaminant molecules such as sulfur in the air, is not supported chemically.


Jim