Gold closed below $900 for the first time in five weeks and copper sank to a six-month low Tuesday as falling crude prices and a stronger dollar fed selling of hard assets.

Other commodities traded mostly lower, with corn, soybeans and other agriculture futures falling. The declines are the latest sign that the commodities boom of the past year is at least temporarily losing momentum as a weak U.S. economy curbs demand for energy and raw materials.

Gold dropped more than $20 during the day as the dollar ticked higher versus the 15-nation euro, diminishing demand for the metal as a hedge against inflation.

The dollar held its ground Tuesday after the Federal Reserve, seeking to revive the economy and stem inflation, decided to keep its benchmark interest rate steady at 2 percent as expected. The Fed said credit tightness, a weak housing market and high energy prices would likely “weigh on economic growth over the next few quarters.”

Gold for December delivery fell $21.80 to settle at $886.10 an ounce on the New York Mercantile Exchange, after earlier dropping to $883.70, the lowest level since July 25.

“Gold showed once again that it is feeling the impact of an oil price that has shed some $30 from its recent record price and continues to aim lower,” Jon Nadler, analyst with Kitco Bullion Dealers Montreal, said in a note.

Other precious metals also sank. September copper dropped 2.3 cents to settle at $3.417 a pound on the Nymex after earlier falling to $3.3765, its lowest level since February 7.

Silver shed 10.568 cents to settle at $16.572 an ounce on the Nymex after earlier falling to a six-week low of $16.475.

Crude tumbled further Tuesday as concerns mounted that a U.S. economic slowdown and high energy prices are eating into consumer demand for fuel.

Light, sweet crude for September delivery fell $2.24 to settle at $119.17 a barrel on the Nymex, after dipping earlier to $118 _ the lowest level since May 5, and nearly $30 below the trading high of $147.27 reached July 11.

Other energy futures also dropped. Heating oil fell 6.81 cents to settle at $3.2820 a gallon, while gasoline lost 4.38 cents to settle at $2.9564 a gallon.

In agriculture, wheat prices rallied on expectations that recent selloffs have been overblown. Wheat for September delivery fell 21.25 cents to settle at $7.80 a bushel on the Chicago Board of Trade.

“The feeling is that we’ve sold off enough. We don’t need to go down any more,” said Vic Lespinasse of Grainanalyst.com.

Meanwhile, corn and soybeans turned lower as ideal growing weather in the Midwest boosted traders’ expectations of a good fall harvest despite devastating June flooding.

Soybeans for November delivery fell 26 cents to $12.69 a bushel on the CBOT, while December corn lost 10.5 cents to $5.45 a bushel.