As of Thursday's close, the price of gold has fallen nearly 23% in the second quarter, setting up the yellow metal for its worst quarterly loss since President Nixon ended the dollar peg in August 1971. In the following video, Fool contributor Alex Dumortier explains the reasons behind this decline and provides investors who own physical bullion, the SPDR Gold Shares (GLD 2.21%), or the Market Vectors Gold Miners ETF (GDX 2.81%), with a clue to the question that is now at the top of everyone's mind: How much lower can gold fall?