The Gold standard also failed the Spaniards back in the 1500's. They brought so much gold back from the New World they experienced 500% inflation.
I am going to look hard at the events Gungeek is talking about; but the influx of Gold from the New World is the only real time that I know of that the value of gold went down for actual physcical non-flim-flam reasons.
The Keynsian fiat flim flammers don't want currency tied to reality because governments like creating money out of thin air; but the charade cannot last forever. The only precious metal backing our fiat paper is aircraft grade aluminum formed into B-52 bombers. Folks take our money because we can and do blow folks up.
That is where I am at in my dull world of groping and wandering about in the dark. Gonna go back and re-read "The Case for Gold"