Gold prices slipped on the Comex division of the New York Mercantile Exchange Monday with the dollar index slightly higher. The dollar gained 0.1 percent on the International Exchange to 81.69. Gold shed $6.50 to $1,666.40 per troy ounce. Silver added 6 cents to closed at $30.77 an ounce. The euro fell to $1.2497 from Friday\'s $1.2512. Against the yen, the dollar rose to 78.76 yen from 78.65 yen.