Gold futures dropped suddenly, losing almost 1 percent of their value in about 15 minutes.
Trading volume also picked up during the selling activity.
Gold futures for December delivery were down 0.9 percent as of 11:52 am in New York after stabilizing following the sudden decline.
It was not immediately clear what caused the drop.
Gold was set for a weekly gain as stocks fell and uncertainty about the timing of the U.S. tax reform plan increased, pushing investors into the arms of the safe-haven trade.
