I was thinking about this while I was on the bus the other day. Diamond I
 can see going for a significant amount (it has a fair few industrial and
 commercial uses) 
Diamond is a bad example. Thank DeBeers.
  though the only use I could come up with for gold was
the
 plating on edge connectors... 
Plating on a whole lot of other things as well.
  Didn't manage to think of a single commercial or
 industrial use for silver at all... 
Plating and contacts. I think (much) more silver is used by industry than gold.
Wiki for more info.
--
Will