Comex gold prices are trading modestly lower Monday morning as the U.S. dollar index is trading higher, which has most commodity futures markets are under some selling pressure. Gold prices in late trading Friday rose to a new all-time record high of $1,398.70 an ounce, basis December futures. December Comex gold last traded down $5.40 at $1,392.30 an ounce Monday morning.  Spot gold last traded down $0.90 at $1,393.50.