Silver and platinum decline in anticipation of Bernanke's testomony

SINGAPORE (July 17)  Silver was down 1.1 percent at $19.77 an ounce, tracking gold. Spot platinum was down 0.7 percent at $1,413.49 an ounce, while spot palladium was down 0.8 percent at $727.95 an ounce.

Platinum's premium over gold held at around $130 an ounce on Wednesday, close to this week's near two-year high of $140.

Platinum prices are taking support from the threat of supply outages in major producer South Africa as wage negotiations between mining companies and unions grind on.

"The platinum group metals and gold were buoyed by a wage impasse as the mining unions rejected the Chamber of Mines' initial offer for a 4 percent pay hike," HSBC said in a note.