Gold rose to its highest level in more than a month on Friday, gaining 1 percent as a combination of dollar decline, options-related buying and technical support sent the metal near $1,750 an ounce.
After trading slightly higher in early U.S. dealings, gold suddenly surged and broke above its 50-day moving average, a key technical resistance the metal had failed to breach in more than a month.
Bullion also benefited as the dollar fell broadly, particularly versus the euro, on hopes for a Greek aid package and a surprise improvement in German business sentiment.
"The dollar here is just getting smacked so hard in a really thin market, so it's easy for gold and silver to break out of some key levels without a lot of resistance," said Matthew Schilling, commodities broker at futures brokerage RJ O'Brien.
"It's a dollar play today," he said.
Strong buying related to next Tuesday's expiration of the popular December COMEX options also lifted gold. Heavy positioning of the $1,750 and $1,800 strikes in call options could increase volatility and lift prices, traders said.
Markets could be choppier than usual in thin trading on Friday, with the metal markets closing early and the U.S. stock market open for only a half-day of business after the U.S. Thanksgiving holiday on Thursday.
Spot gold was up 1 percent at $1,747 an ounce by 11:07 a.m. EST (1607 GMT).
U.S. COMEX gold futures for December delivery were up $18.90 an ounce at $1,747.10 in heavy trade. The first-notice day for December is next Friday.
Among other precious metals, silver rose 1.7 percent to $33.83 an ounce. Platinum was up 1.3 percent at $1,600.50 an ounce, while palladium gained 1 percent to $660.97 an ounce.