Gold prices edged lower on Tuesday as the U.S. dollar firmed, while investors hunkered down for Federal Reserve Chair Jerome Powell's speech at Jackson Hole later this week.

The Nasdaq fell as megacaps lost, after having rallied for much of the year. Nvidia fell 3.5%, the biggest drop in nearly four months.

Yardeni Research president Ed Yardeni believes Fed chair Jerome Powell won't give away his hand when he speaks in Jackson Hole this week.

By Howard Schneider WASHINGTON (Reuters) -Fed Chair Jerome Powell used the central bank's annual Wyoming research conference to promise inflation-fighting rigor when it was needed in 2022, then last year he came to the defense of the job market with promises of lower interest rates when the unemployment rate seemed on a steady rise.

Chair Jerome Powell in remarks on Friday is expected to unveil the Fed’s new policy framework — the strategy it’ll use to achieve its inflation and employment goals. Powell may also drop some hints about the Fed’s thinking ahead of its September policy meeting.