The ore icon is unofficial, its of a coin. Its purpose is to be as an illustration.
The Pile of Gold is an unobtainable ore that does not award XP or items. It is found on the surface of the Helen Quest room. It has a moderate mining time. Upon mining, it drops several gold coins, but can not be interacted with. Similarly to Memerock and Dragonstone, it's unobtainable.