Weak China data sinks gold, silver markets Gold and silver prices are lower in midday U.S. trading Tuesday. The two precious metals were pressured following surprisingly weak import and export data coming out of China overnight. A rally in the U.S. dollar index and weaker crude oil prices also weighed on the metals today. December gold was last down $9.60 at $1,960.50 and September silver was down $0.437 at $22.79. Risk appetite receded following the news that China got some…