* TSX falls 120.31 points, or 0.93 percent, to 12,806.47 * Nine of 10 main index sectors decline * BlackBerry tumbles 16 percent * Barrick, Goldcorp have biggest negative influence on market By John Tilak TORONTO, Sept 20 (Reuters) - Canada's main stock index slumped on Friday as shares of BlackBerry tumbled after it warned of job cuts and a huge quarterly loss, and uncertainty surrounding the U.S. Federal Reserve's monetary policy strategy weighed on sentiment. BlackBerry dropped 16.1 percent to C$9.08, and the announcement is expected to put more pressure on the embattled smartphone maker to find a buyer. A cloud of doubt hovered over a market trying to make sense of different messages from the Fed about its massive bond-buying program. While the market at first blush cheered the U.S. central bank's move on Wednesday to leave its stimulus program in place by maintaining its $85 billion a month in bond buying, investors have tried to analyze the implications and look for clues about when the eventual scaling-back of its bond buying could happen. The Fed could still begin unwinding the program at its October meeting if data showed the economy was getting stronger, St. Louis Fed President James Bullard said. Gold-mining shares were hit by weakness in the price of bullion, which remained volatile after the Fed's statement. "Certainly the water is quite muddy at the moment," said David Cockfield, managing director and portfolio manager at Northland Wealth Management, adding investors were very confused about the Fed's next steps. The Toronto Stock Exchange's S&P/TSX composite index closed down 120.31 points, or 0.93 percent, at 12,806.47. "I'm not betting the farm on the Canadian market taking off," Cockfield said. "There are some huge headwinds." He said sentiment for Canadian equities was beaten down, with investors finding U.S. stocks more attractive. Nine of the 10 main sectors on the index were in the red. The materials sector, which includes mining stocks, slipped 3.6 percent. Gold producers lost 5.5 percent as bullion stumbled. Barrick Gold Corp declined 4.2 percent to C$19.11, and Goldcorp Inc shed 3.8 percent to C$26.96, playing the biggest role of any two stocks in leading the market lower. Financials, the index's most heavily weighted sector, gave back 0.3 percent. Royal Bank of Canada, the country's biggest lender, slipped 0.4 percent to C$65.96; Bank of Nova Scotia fell 0.7 percent to C$59.21. Shares of energy companies lost 0.4 percent. Canadian Natural Resources Ltd was down 0.4 percent at C$32.40, and Suncor Energy Inc stumbled 0.6 percent to C$36.89.