Gold prices fell modestly on the Comex division of the New York Mercantile Exchange Thursday with equities mixed on Wall Street. The dollar index was flat, falling 0.08 percent to 76.98. Gold lost $13.70 to reach $1,668.60 per troy ounce. Oil gave up $1.09 cents to reach $84.48 per barrel. The euro fell to $1.3785 from Wednesday\'s $1.3791. Against the yen, the dollar fell to 76.85 yen from Wednesday\'s 76.26 yen. The British pound rose to $1.5772 from $1.5752. The U.S. dollar fell to 7.7763 Hong Kong dollars from 7.7791 HKD. The U.S. standard rose to 1.0195 Canadian dollars from 1.0175 Canadian. The Australian dollar rose to $1.0202 from Wednesday\'s $1.0158.