People have blamed gold's 18 percent decline this year on many different factors: a lack of fear in the market, a bubble that has burst, talk that the Federal Reserve will soon end qualitative easing. But some market participants say the single biggest factor could be the Japanese yen.

"It is difficult to deny the strong correlation between the yen's decline and the consequent collapse in gold," said Jim Iuorio, TJM Institutional Services managing director and contributor to CNBC.com's "Futures Now."