What substance will turn from black to red when heated? My grandmother gave me a bowl, saying it was given by lectures, and there was a blessing on the outside.
Ferrous oxide is black, and if it is converted into iron oxide, Fe2O3 is red, and if it is converted into salt ions, it is red. Ferrous oxide is a substance produced by burning iron in pure oxygen, and ferric oxide can be formed by burning or standing in the air for a period of time.