Well the gold often mentioned is more "shiny stuff" that lay around the surface imo, just if someone else considered it valuable.

Gold in the ancient times was on the surface of the earth and in caves... But for obvious reasons it isnt anymore. Howvere, I don't think gold has much of a purpose anymore (don't think it can do much platinum can't).

Water is also kinda worthless so the anology doesn't really follow I don't think... Most of western europe have springs and lakes that carry drinkable water (not sure about the rest of the world).