Jim Browning writes:
DeBeers has controlled (or at least significantly influenced) the price of diamonds for decades, ensuring that they appreciate in value by controlling supply, and by buying diamonds on the wholesale market to keep the price up (similar to what countries do to protect their currencies). They could flood the market at any time, driving the price down dramatically. Of course this isn't in their best interest, so they won't do it. However Russia might, as they have stockpiled large quantities of diamonds, and may not have the same goal as DeBeers...
So in what way is this a demonstration of a monopoly able to arbitrarily raise prices? What you've shown is that someone might be able to arbitrarily drop prices... .pm