Gold futures rose early Tuesday, extending their prior session gains on higher oil prices following attacks on pipelines in Nigeria and amid continued concern about Iran's nuclear research program. Gold for April delivery was last trading up $1.10 at $555.70 an ounce. Silver added 10.5 cents to $9.525 an ounce. Platinum was up $12 at $1,023 an ounce and palladium rose $3.25 to $292 an ounce. Copper rose 4.40 cents to $2.245 a pound