Cast Iron and electric stoves?
Question - will cast iron still turn black even if it's being used on an electric stove? If so, will it take longer than cooking over a fire?
Cast iron will turn black, no matter where you're cooking. It will likely take a little longer to turn simply because the heat is concentrated to the bottom of the pan. On a gas range, you're going to get some extra heat slipping up the sides. If you're concerned with seasoning, why not put it in the oven? It'll turn pretty black in there.
I've cooked on electric for the past 40 or so years. My cast iron pan is black as can be. It didn't take 40 years to get that way . . . . .