"You've had so much come out of the ETFs, " said Frank McGhee, head precious-metals dealer with Integrated Brokerage Services.

WSJ: Gold Rally May Lose Steam

"There was just an avalanche of stop-loss selling, " said Steve Murton, head of precious metals at Triland Metals, a brokerage firm in London.

WSJ: Gold's Great Unraveling Had a Few Harbingers

For platinum to surpass the yellow metal for a sustained period, two things would need to happen, said Tom Kendall, head of precious-metals research at Credit Suisse.

WSJ: Platinum Signals Nagging Economic Worries