Gold prices rose Thursday as Greek officials said they were optimistic a debt swap would include enough participants to qualify Greece for international aid. The dollar index, a prorated measure of the greenback against six major currencies, fell 0.68 percent to 79.16, giving commodities priced in U.S. dollars a boost. Gold prices on the Comex division of the New York Mercantile Exchange added $16.90 to reach $1,700.80. Silver added 31 cents to $33.90. The euro rose to $1.3273 from Wednesday\'s $1.3149. Against the yen, the dollar rose to 81.54 yen from 81.09 yen. The British pound fell to $1.583 from Wednesday\'s $1.531. The U.S. dollar rose to 7.7571 Hong Kong dollars from 7.7559 HKD.