Sorry, but this is such an urban legend.  Don't get me wrong, I like gold and silver, but they do not automatically maintain purchasing power.  Somebody who bought gold in 2000 made a hell of an investment, an can now buy a boatload more other stuff then he could then.  It is true that if you look at gold historically, then it maintains its purchasing power a lot better than fiat currencies, but in the short term (short being decades here), this is simply not true.  This is why I also don't see gold as a "safe" investment, next to the volatility being quite large.  There might be times when it is the safest asset to buy, but definitely not allways.