In the image above, the dark green rings are ferrous sulfide rings, caused when the sulfur from the egg white reacts with the iron in the egg yolk when the egg is overcooked.
I was wondering, given the same circumstances, why do we not see our scrambled/fried eggs coated with this layer of ferrous sulfide?
Scrambled eggs can change color, but you perhaps haven't run into a batch that shows discoloration. It is the same chemical reaction:
Why Scrambled Eggs Turn Green
When serving a large group, a buffet can provide enough food for everyone without the need to spend all of your time in the kitchen. Breakfast is a fairly simple buffet to set up, but there are special challenges when it comes to scrambled eggs. When scrambled eggs sit for a while, they tend to turn green or gray. This is a chemical reaction that happens as hydrogen sulfide in the egg white reacts with the iron in the yolk to form iron sulfide.