Metals and energy prices are ending lower across the board, while crop prices are mixed.
The actively traded December contract for gold fell $4.80 to $1,324.80 an ounce. September silver lost 18.4 cents to $19.68 an ounce. Copper, platinum and palladium also fell.
Crude oil fell to the lowest price in four weeks as traders wait for an updated policy statement from the Federal Reserve Wednesday and other key economic news, including the government's monthly employment report on Friday.
Benchmark oil for September delivery fell $1.47 to finish at $103.08 per barrel on the New York Mercantile Exchange.
In agricultural futures trading, December corn rose 4.25 cents to $4.775 a bushel. September wheat rose 3.75 cents to $6.5525 a bushel and November soybeans fell 17 cents to $12.03 a bushel.