The metal broke below its 200-day moving average, which it had held for four months, as safe-haven bidding faded following a government report that showed the U.S. economy grew at a faster-than-expected 3.1 percent annual rate in the third quarter.

Silver also dived over 3 percent and platinum group metals each fell around 2 percent.

Also weighing on gold was news Morgan Stanley Smith Barney has recommended its financial advisers pull client money out of long-time gold bull John Paulson's funds. The announcement stirred speculation the billionaire hedge-fund manager might need to liquidate gold investments.

"There is a concern among the hedge funds that they will have more redemptions because of the fact that they underperformed the markets this year as a whole," said Jeffrey Sica, chief investment officer of SICA Wealth Management which has over $1 billion in assets.

U.S. Comex gold futures for February delivery settled down $21.80 at $1,645.90 an ounce, with volume in line with its 30-day average, preliminary Reuters data showed.

Spot gold was down 1.1 percent at $1,647.40 an ounce by 4:13 p.m. EST (2113 GMT), having hit a low of $1,635.09, which marked the weakest since Aug. 22.

Silver, which often displays higher volatility than gold, was down 3.4 percent to $29.94, having hit a four-month low of $29.60 an ounce.

Bullion has now fallen 3 percent in the last three sessions, partly pressured by uncertainty related to efforts by U.S. legislators to clinch a deal to avert automatic tax hikes and spending on Jan. 1.

Gold has failed to benefit as a safe haven even though a year-end deadline for the "fiscal cliff" looms. On Thursday, Republicans in the U.S. House of Representatives pushed ahead a "fiscal cliff" plan that stands no chance of becoming law as time runs short to reach a deal with President Barack Obama to avert a Washington-induced economic recession.

After this week's sharp sell-off, bullion is on track to end the fourth quarter down 7 percent, which would be its worst quarterly performance since the second quarter of 2004.

OPTIONS, TECHNICAL OUTLOOK BEARISH

Heavy concentration of put options under $1,700 an ounce added significant pressure on the underlying gold futures. Many investors have accumulated puts at lower prices to protect their gains in gold futures.

On charts, Thursday's sell-off sent gold's 14-day relative strength index to 25, the area which is considered by most analysts as oversold, for the first time since May.

Year to date, gold was up around 5 percent. It was up as much as 15 percent earlier this year on worries that monetary easing by the Federal Reserve could spur inflation.

Among platinum group metals, platinum dropped 2.7 to $1,544.50 an ounce, while palladium slipped 2.1 percent to $676.50.