SAN FRANCISCO (MarketWatch) -- Gold futures dropped more than 3% on Thursday to mark their lowest close in more than three years following the Federal Reserve's decision to taper its asset-purchase program and a rally in the U.S. dollar. February gold gcg4 sank $41.40, or 3.4%, to settle at $1,193.60 an ounce on the Comex division of the New York Mercantile Exchange. Futures prices, tracking the front-month contracts, haven't closed at a level that low since Aug. 3, 2010, according to data from CME Group.