Updated from 1:23 p.m. EST

Gold futures reversed ground and ended lower Monday after a modest morning rally petered out.

February-dated bullion contracts closed down $2.30 at $634.10 an ounce on the Comex division of the Nymex. The exchange-traded funds that hold bars of the metal, streetTracks Gold Shares ( GLD) and iShares Comex Gold Trust ( IAU), were lower by 0.3% and 0.4%, respectively.

"Short-term profit-takers locked in a quick profit," says Jon Nadler, an analyst at Montreal-based bullion dealer Kitco, who noted that the advance ran into heavy resistance at about $640.

He adds that longer-term investors should provide the market with solid support going forward. "New pension funds are looking at jumping in to the precious metals space , and we're seeing some before tax-season realigning," Nadler says.

Adding to the downward pressure was a slightly stronger dollar. One dollar was buying 121.65 yen, up from 121.23 yen late Friday. A euro would buy $1.295, vs. $1.2963 previously. Bullion prices tend to move in the opposite direction of the greenback.

With little by way of new economic data expected during the first half of the week, some investors may be waiting to hear President Bush's State of the Union speech Tuesday evening before committing significant new positions. Particular attention will likely be paid to any comments affecting energy, the U.S. economy and geopolitical issues.

In the gold patch, the Market Vectors Gold Miners ( GDX) ETF was moving down 0.7% recently, while Yamana Gold ( AUY) was down 0.8%.

Elsewhere, shares of Freeport-McMoRan Copper & Gold ( FCX) were losing 2.2%.

Turning to the base metals, Comex copper contracts closed up a penny at $2.53 a pound.

Alcoa's ( AA) shares were recently losing 0.5% after Standard & Poor's downgraded its credit rating on the aluminum smelter.

The "action reflects our concerns and uncertainties about the impact the share repurchase program will have on the company's ability to reduce debt levels," an S&P press release stated.

As for news affecting the ferrous metals, Deutsche Bank upgraded shares of AK Steel ( AKS) to a hold rating from sell.

"Earnings growth in a declining market ... and M&A possibilities should continue to support the stock in 2007," the firm stated in a research summary. AK Steel's shares were recently up 0.4%.