The non interest earning gold
This is a very crude way to discuss. If you'd read Rothbard you will see he never talks about some fiat-currency but gold ounces and that even those earn their interest.
That it's not so with current gold is simply because gold is calculated in whatever fiat-money you can think of.
And you do not lend Gold but "money" , as we know this money is not real money, but that's another story
Still since 2001 gold has risen from around 300 USD/ounce to well over 1800 USD/ounce in 2011 that means the you need six times more money today to buy one ounce.
That are a little below 20% raise for now 10 years, and the last 3 years the raise has risen to 27%/year. So if you'd spend 1000 USD in 2001 in Gold you know could get back 6000 USD and well the inflation rate is quite a bit lower
On the other hand the interest yielding Euro money today yields 1.976 % for 10 years. In Germany we'd have to pay 0.4xx % taxes on it and inflation rate is near 2.5%. You're loosing a percent every year.
If we just would calculate with double the interest for the past 10 years and you'd invest 1000 USD for 10 years you and without taxes you'd now have 1343 USD. Now talk about the "great" interests this money earns....
Because all central banks and politician try to devaluate their currencies one just can buy gold, sit back and watch. The madness will come to an end. Do you think you will fare better with fiat-money or Gold?
Well I for my part have decided that for me....