@dyslexia,
I've been thinking about that very thing.
Lets see; the agricultural commodities are valuable because they can ultimately be eaten or woven into fabric; fuels can be burned for energy; metals (other than gold) have industrial uses. Gold seems to be traded and hoarded because it has value based on someone else's desire to own it. That is, it has value because it has value, which at least sounds like very circular reasoning.
I very much suspect that if one person acquired all the world's gold reserves, there would be no market, and we would suddenly realize the emperor was nekkid.
Alright, it makes shiney jewelry that doesn't make your skin turn green, but if it were as cheap as brass it would be quickly out of style.