Gold powered through resistance at $430 an ounce, mainly tracking the euro, with which it has a strong correlation.
A lower US currency tends to boost metals, which are mostly priced in dollars world-wide, because they get cheaper for non-US buyers.
"There was good fund buying earlier, but the dollar has come back up a little bit and we backed off the highs in gold and silver," said James Quinn, AG Edwards & Sons commodity commentator.
Brokers saw $440 as the next upside target, with support pegged at $430. Gold was primed for a multi-week rally, with the latest Commodity Futures Trading Commission's Commitments of Traders data showing commercial traders are going long in gold, said John Kosar, president of Asbury Research. Rallies in May 2004 and April 2003 began when commercials were similarly positioned, he said, noting commercials often gave a better read to momentum than the large speculators.
Technically, funds also have renewed accumulation of long positions after gold recently bottomed out, analysts said.
The latest weekly Commitments of Traders data showed the fund net long exposure in COMEX gold futures rose to 21,707 lots as of February 15 from 11,175 lots a week earlier.
Spot gold priced at $432.30/3.00 an ounce, versus $427.00/7.70 at the London close on Monday. Tuesday's afternoon fix in London was at $432.85. Silver was higher, after bolting above resistance at $7.40, in an extension of a 10-day rally. Silver, which has merits of both precious and industrial metals, also has been supported by copper's recent race to a 16-year high. March silver rose 5.8 cents to $7.475 an ounce, trading from $7.365 to $7.57 - its loftiest level since December 8. Spot reached $7.45/48 from $7.39/41 previously in London. The fix was at $7.55.
CFTC data showed the silver fund net long exposure rose to 36,974 lots from 27,763 lots previously. April platinum climbed $7.50 to $873 an ounce. Spot touched $872/876.
March palladium rose $1 to $184 an ounce. Spot stuck around $180/184.