Yup, you're absolutely right Thad. There's millions of dipped coins in slabs. But how many over-dipped coins do you know of that are in slabs ? You know as well as I do that until Genuine and Details slabs came along NGC and PCGS body-bagged over-dipped coins on a daily basis. You also know that with Jewel Luster you cannot dip a coin for more than 1 second or all luster will be destroyed.
If it is as you say, than it must have been diluted. Because the coin still had full cartwheel luster when completely finished with the process.
Will it at least stay as is, or will the silver corrode over time since it has reached the black tone stage?
That black tone is what's protecting the silver from corrosion, not corrosion itself. All metals have a similar reaction. Copper turns green, silver black, iron red, and so on. Every time you strip that protection off, you expose the metal to contaminants and speed it's demise.
It's not black, merely dark grey. It's what I and many others would call gun-metal grey. That's what older silver coins are supposed to look like when they haven't been messed with. And yes, it'll stay just like that, for your lifetime at least, in an Air-Tite as long as you store it correctly.
Maybe, I dunno. But don't take my word for it, see for yourself. Go buy some Jewel Luster. Take a new coin, a clad quater or dime, a cent - any new coin that has ful luster. Dip it in the Jewel Luster for 10 seconds and look at what happens. I absolutely guarantee you it won't have any luster left. Uhhh - yes, it is.
