Gold lost some sparkle as investors took a cautious approach ahead of the Jackson Hole meeting on Friday.
An hour after US trading got underway spot gold was more than US$12 lower at US$1,325.
Unless there is major recovery after the meeting, it puts gold on course for its first monthly decline since May.
Speculation over the timing of a US interest rate rise has been the main reason gold has slipped recently though it is still 25% higher year-to-date.
Markets are currently pricing in around a 20% chance of a rate rise next month with a rise in December being seen as an even bet.
A rate hike may be justified some Fed members have suggested if the US jobs markets continues to grow at the pace seen recently, though Federal Reserve chair Janet Yellen is seen as being in the dovish camp.Yellen is a key note speaker at the meeting of central bankers in Wyoming.
Other precious metals were dragged lower by the dip in the gold price. Silver eased to US$15.58 while platinum tumbled US$26 to US$1,075.