Looks to be Plating bubbles. So your partially correct in what you thought it was. It is the same metal..
I see something different in the photos. Simple chased metal? Q1. What date is the cent? Q2 Does it appear like there is a dent/scrape on the field & there is metal higher than the field to the top & right of the dent/scrape?
It's a 1993D. It's not bubbles and it's not hollow metal. There ias a scrape mark. It looks like something scraped it when the metal was soft/hot. something scraped it and pushed the hot metal away and it blobbed up and cooled.
what you have here looks as if it may be what we call zinc rot. on these copper plated coins sometimes the copper plating becomes damaged and this allows the zinc inner core to start to rot and swell up under the copper plating.
Hello tomfiggy, Thanks for letting me know the date. Do you have any books that describe the minting process? Errors can be more easily described and authenticated if you know how the coin is made at the mint. I would recommend "The Error Coin Encyclopedia by Weinberg & Margolis. I also recommend Mint Errors by Alan Herbert. Weinberg & Margolis signed my latest copy when we met at the FUN show several years ago. Alan signed my copy when we met at the Boston ANA a couple years back.
Great Advise! Hang onto them books Collect89.. you know that Alan and Arnie both have passed on so the signed copies will be no more.
