Silver touched a six-month high, but platinum fell $5 an ounce to trade way below last week's record high levels.
Spot gold was quoted at $639.10/640.10 an ounce by 1113 GMT, against $638.10/639.10 in Europe late on Friday. The metal rose as high as $641.75 an ounce in Asia.
"At $640, people sold and locked in some of the profit, but overall gold looks very strong. There is more upside (potential) at the moment than downside," said Michael Widmer, metals analyst at Calyon Corporate and Investment Bank.
"People have become more confident towards gold and less confident towards the dollar. There is enough evidence for the dollar to stay weak in the next few months."
The dollar backed away from a 20-month low hit earlier against the euro and a three-month trough versus the yen, as comments from France's finance minister cooled last week's euro rally.
A weaker dollar makes gold cheaper for holders of other currencies. The metal is also generally seen as a hedge against inflation.
Oil rose one percent towards $60 a barrel after Saudi Arabia's oil minister said OPEC may cut output further when it meets on December 14.
The gold market was likely to remain choppy on Monday as U.S. investors would return to the market after holidays.
"U.S. traders returning after their long Thanksgiving holiday may look to unwind some weekend longs, taking advantage of the market over $10 higher than Wednesday's close," said James Moore, precious metals analyst at TheBullionDesk.com.
"But the combination of strong technical outlook, weak dollar/firm oil should see gold target $650 in the coming sessions," he wrote in a daily market report.
Dealers said firm gold prices were expected to hit physical demand in key consuming nations.
The World Gold Council said Saudi Arabia's third-quarter gold demand fell 9 percent to 33.9 tonnes compared with the same period in 2005 as high prices and a downturn in the local bourse dampened sales.
"The market is in a nice upward trend after breaking through a key level today based on the dollar's weakness," said Shuji Sugata, assistant manager at Mitsubishi Corp. Futures and Securities Ltd.
"We are more convinced that the outlook for gold will stay strong in the longer term," Sugata said.
Silver rose as high as $13.54 an ounce before dropping to $13.46/13.53, against $13.39/13.46 on Friday.
Platinum was quoted at $1,180/1,190 an ounce, down from $1,185/1,200 on Friday. The metal had surged to a record high of $1,395 last Tuesday. Palladium was at $326/331 an ounce, up $1 from its precious close.
