By Millie Munshi

Nov. 20 (Bloomberg) -- Tumbling prices for oil, copper and natural gas sent the Reuters/Jefferies CRB Index of 19 raw materials down more than 50 percent from a record in July as the global recession sapped demand.

Crude oil fell below $50 a barrel for the first time in almost two years. Copper touched the lowest price since July 2005, and corn dropped to its lowest in almost 13 months. The CRB lost as much as 2.8 percent to 233.73, the lowest since July 31, 2003. The index touched 473.97 on July 3, its highest ever.

First-time claims for U.S. unemployment insurance jumped to the highest level since 1992, and manufacturing in the Philadelphia area shrank this month at the fastest pace in 18 years. More than $32 trillion has been erased form the value of global equities this year as the U.S., Japan and some European nations fell into recession.

"There are tremendous amounts of economic distress," said Michael Pento, who helps oversee $1.5 billion at Delta Global Advisors in Holmdel, New Jersey. "Everywhere you look there are horrible economic numbers from now to as far as the eye can see. Commodities are getting killed because the appetite for these things has completely disappeared."

The CRB is down 32 percent since the end of September, after a 25 percent plunge in the third quarter that was the biggest quarterly decline since 1956, when the data begins.

Crude oil for December delivery fell $2.62, or 4.9 percent, to $51 a barrel at 11:21 a.m. on the New York Mercantile Exchange, after earlier dropping to $49.75.

Copper lost as much as 3.6 percent to $1.552 a pound on the Comex division of the Nymex. That's the lowest since July 15, 2005. Natural gas, the biggest loser in the CRB index today, was down as much as 8 percent.

Gold was the biggest gainer today, rising as much as 2 percent to $750.80 an ounce on the Comex. Some traders buy the precious metal as a haven during financial turmoil.

"Gold will perform well as fear takes hold and as the risk appetite has completely left the market," Pento said.