Chemically - iron is above hydrogen in the Electrochemical Replacement Series and will displace Hydrogen from acids. Gold is below hydrogen and does not displace hydrogen at all. It is almost inert chemically, which makes it so useful in so many specialised applications. Only Aqua Regia will dissolve gold, then very slowly and it releases oxides of nitrogen in the process. Iron remains VERY chemically active - having several complex valencies and a mind-numbing number of chemical reactions.
Gold does not oxidize, and is extremely conductive. (most conductive materials lose conductivity as they oxidize, since gold does not oxidize, it never loses conductivity making highly valuable for electronics (a lot of the parts in your phone are gold). it is also highly malleable, and keeps most of it's properties even when hammered paper thin. (radiation doesn't penetrate it, that is why gold foil is used to protect satellite components)