Gold prices edged up on the Comex division of the New York Mercantile Exchange Friday, adding $6.30 and settling at $1,566.90 per troy ounce. Silver lost 23 cents and closed at $26.81 per troy ounce. The dollar index fell 0.09 percent to 82.24 on the Intentional Exchange, helping boost commodities traded in U.S. dollars. The euro rose to $1.2566 from Thursday\'s $1.2541. Against the yen, the dollar rose to 80.46 yen from Thursday\'s 80.29 yen.