I just got this 1945 Norway 5 Ore. This morning while I was opening the envelope outside the post office it slipped out of my hands and landed on the sidewalk. It now has a chip along the rim. Before After: I checked the coin with a magnet and confirmed it was iron as it was magnetic. My question is, does iron chip easily when dropped on a hard surface like a sidewalk. I didn't get a good look at the coin before I dropped it so I'm not 100% sure the chip was there to begin with.
Iron is a fairly hard and brittle metal so it wouldn't surprise me that a coin would chip. Sorry, that sucks.
I don't know anything about these particular coins - were they iron that was coated or plated with something ? I ask because you used the word chip and to me that implies that a small piece actually broke off. And in a way that's kind of what that looks like - an iron core that was plated with another metal. The outer plating chipped off revealing the darker iron core inside - which is now dented by the way. And that darker color is definitely not in your first pic - nor is the rim ding/dent. So if you can confirm that these coins were as I described above, an iron core that was plated, than I'd say you have it exactly right - it chipped.
Typically information like that is provided, mentioned, in the books that catalog the coins of a given country by giving you the coin's composition. Now I don't know this for an absolute certainty when it comes to the coins of other countries, but typically when a coin is made of iron or steel it is almost always coated or plated with another metal that more resistant to corrosion than iron or steel is. I would expect that you can find this info in the Krause catalogs. Think of the US steel cents of WWII, they were coated with zinc precisely for that reason.
Your link doesn't say one way or the other, it just says iron. But if you have the coin in hand it should be a simple matter to look at it closely under a loupe and see if it was coated/plated and the coating chipped off. If it has, then you should be able to see the edges of where that coating chipped off. If you can't see anything like that, then I don't know how to explain the differences in your pictures. The before - The after - The black mark and rim ding is definitely there in the after and definitely not there in the before. So the coin being coated/plated, and that plating chipping off when it was dropped, is the only explanation that seems to make sense to me. Could I be wrong ? Sure, but I don't know how else to explain what we see.
