coin beach

My wife found this while snorkeling. We can't quite make out the coin, and I realize these pictures don't help much, but truthfully there isn't much more to see. What i'm wondering is, how long does it take for this to happen to a coin? It's probably copper or iron for it to turn itself...

This was found on the beach in lower Delaware by a friend last winter. He asked if I could try to get it identified for him. I am hopeful that it is a shipwreck relic of some sort. I was reluctant to do a silver test on it since it isn't mine but it looks good. Thanks for your input, I am sure...

I found this ?piece of ceramic? After spending 2 hours on the beach. The coin is just there to show size. The piece is light and has smooth edges. It's not polished but dull, and feels almost like a chalk consistency. Any idea on how to tell if its old or not? I was hoping to find a coin but...

I am new to TreasureNet and MDing. I went to Coin Beach this weekend and I only got one hit, the attached pics. I got a Silver reading from it. It was encrusted with rust. As I was looking at it, it slipped from my hands and crashed onto the cement floor and some of the rust came off. I have...