Platinum futures prices plunged the limit allowed for daily trading Wednesday on expectations of an economic slowdown.
On other markets, oil futures fell sharply; grain and soybeans rebounded after two days of losses; livestock and meat were mixed, and stock market index futures were unchanged.
Futures on platinum and silver, both primarily industrial metals, fell steeply on New York's Commodity Exchange as hopes for a reduction in the federal budget deficit began to fade, analysts said.
"People are very disturbed that Washington is not moving on this deficit matter, said Sharon Ziemian, an analyst in New York with Citibank.
"People are starting to . . . pull their money out of things, thinking maybe the recession will be even deeper than was previously feared," she said.
Platinum settled $25 lower, the daily limit, across the board with the contract for delivery in December at $497.30 an ounce; gold was $2.20 to $3.40 lower with December at $468.20 an ounce, and silver was 13.9 cents to 18.9 cents lower with November at $6.663 an ounce.
Crude oil futures, trading around $20 last week, broke below the $19 barrier on the New York Mercantile Exchange.
Selling was linked to a growing sentiment that the bickering OPEC nations will not reach agreement on prices or quotas when they meet early next month, said Peter Beutel, an analyst in New York with Elders Futures Inc.
Saudi Arabia's announced intention not to support a price increase helped drive futures prices lower, as did American Petroleum Institute figures released Tuesday that showed a dramatic increase in crude oil inventories, Beutel said.
The API numbers also indicated that stocks of refined products may be on the rise, he said.
The closely watched December contract settled above $19 after falling as low as $18.85, but all other contracts finished below $19 a barrel.
West Texas Intermediate crude oil settled 35 cents to 42 cents lower with December at $19.07 a barrel; heating oil was 0.84 cent to 0.99 cent lower with December at 55.23 cents a gallon; unleaded gasoline was 0.61 cent to 0.95 cent lower with December at 50.89 cents a gallon.
Grain and soybean futures rebounded on the Chicago Board of Trade after two days of fairly steep declines.
Cattle futures advanced while most pork futures declined on the Chicago Mercantile Exchange.
Pork futures declined on slow sales to slaughterhouses linked to abundant supplies of pork and live hogs, he said.