Precious metals prices showed some profit booking on higher levels on Wednesday after U.S. Federal Reserve Chair Janet Yellen said that only "gradual adjustments to monetary policy were likely and stressed that global headwinds could hurt U.S. growth. Holdings of the largest silver backed exchange-traded-fund (ETF), New York's iShares Silver Trust SLV, stood at 9591.72 down 19.25 tonnes, from previous business day.