Very good point Will -- DeBeers regulates just how many diamonds are out
in the open market at any time, hence keeping demand at a high and
keeping diamonds from devaluing...  all the while hording immense
amounts of diamonds in its private stash and releasing them at a
controlled rate.
William Donzelli wrote:
   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