Ah, that's a different premise than I was entertaining. I see 0% liklihood of gold (or really, any metal) replacing fiat, for the same reasons we have fiat in the first place -- I've swallowed the hook on this "velocity mismatch" part of Lyn's "technological determinism" idea.

I can see a role for gold as a physical-bearer-asset hard money adjunct, but in that use case I can't see silver being relevant. It serves no additional purpose. I don't see significant numbers of hard money people caring that much about being able to spend $0.25 or whatever to go to the trouble.