The ascendance of market's inflation versus deflation expectations:
There are several ways to look at the $100 per tr. ounce drop of gold . Clearly, since 2011, and strikingly since July, gold has been favored when Treasury bonds are rising relative to the dollar's foreign exchange rate. Likewise, gold is sold when the dollar rises relative to Treasury bonds. This remarkable relationship of bonds and dollars since gold's 2011 high isn't always this tight, but one needs to be aware of it when buying or selling gold.
We can track this relationship intraday with US exchange-traded proxy ETFs by looking at inflexion turning points: