You are correct Henry, Central Bank, Hedge Fund manipulation...

You are correct Henry, Central Bank, Hedge Fund manipulation would account for far more I suspect, however the price of Gold, like oil is set at the margin. People don't actually use Gold to buy groceries, although I see what you mean, more as a means of holding their savings in Gold rather than cash. It also makes an excellent hedge if you believe your economy is tanking as it will hold its value as the value of your currency drops.