Gold and silver prices regained some glitter Thursday on bargain buying, short covering, falling stock prices and worries over weak economic data, which support the likelihood the Federal Reserve will continue its monetary stimulus. The SPDR S&P 500 (SPY) fell 0.62% in heavy volume to 150.40. Spot gold prices rose 0.74% to $1,577 an ounce. On the stock market today SPDR Gold Shares (GLD), tracking a 10th of an ounce of bullion, added 0.78% to