* TSX up 0.91 of a point at 12,603.09 * Index hits highest point since March 2012 * RIM jumps on BlackBerry 10 hopes By John Tilak TORONTO, Jan 14 (Reuters) - Canada's main stock index finished short of a 10-month high on Monday as investor optimism for Research In Motion Ltd shares over the upcoming launch of its BlackBerry 10 devices was offset by falling energy shares. Weakness in the materials sector, which includes mining stocks, also added pressure, while volatile oil prices were a drag on the energy sector. The two heavyweight sectors kept an otherwise positive index in check. RIM shares extended a 13-percent gain made on Friday. The stock added 10.44 percent to C$14.70 and helped the information technology sector gain 2.48 percent. "The investor confidence is brought about simply because of hope, and hope that the new BlackBerry 10 is going to be an answer to their prayers," said Fred Ketchen, director of equity trading at ScotiaMcLeod. "There has been some talk that this is a revival of RIM. We'll have to wait and see," he added. The Toronto Stock Exchange's S&P/TSX composite index finished little changed, up a 0.91 of a point, or 0.01 percent, at 12,603.09. Earlier, it touched 12,636.68, its highest since March 5, 2012. The index, which marked its fifth consecutive day of gains, swung back and forth between positive and negative territories in choppy trade. "There's a lot of indecisiveness out there. People don't really know which way to go and you're getting these markets that aren't really doing much of anything," said Julie Brough, vice president at Morgan Meighen & Associates. Investors kept a close watch on the U.S. debt ceiling talks, seen as a significant catalyst for the markets, with hopes that a compromise will be reached. "There is reasonable optimism that it would be resolved," Brough said. The energy sector was down 0.5 percent, with Canadian Natural Resources Ltd slipping 1.81 percent to C$29.26 and Talisman Energy Inc falling 2.64 percent to C$11.78. Oil prices were volatile, with Brent crude rising to $112 on supply concerns. Encana Corp shares dropped 2.31 percent to C$19.05 after the surprise resignation of the chief executive officer of Canada's largest natural gas producer. The three energy companies were the three biggest drags on the index. Materials stocks, home to mining firms, was down 0.3 percent amid a slew of deals within the sector. Miner Alamos Gold Inc said it will buy Aurizon Mines Ltd for about C$780 million ($793 million) in cash and stock to get access to Aurizon's only operating gold mine, Casa Berardi, in northern Quebec. Aurizon shares jumped 34 percent to C$4.57, while Alamos Gold fell 11.94 percent to C$14.90. Russia's state uranium firm agreed to pay $1.3 billion to take Canada's Uranium One Inc private, as the successor to the Soviet Union's nuclear industry seeks to strengthen its grip on supplies. Uranium One's stock rose 14.52 percent to C$2.76. In other company news, shares of Harry Winston Diamond Corp rose 4.41 percent to C$14.90 on the company's plans to sell its high-end watches-to-necklaces division to Swatch Group in a $750 million cash deal that expands the Swiss watchmaker's luxury offering and lets the Canadian group concentrate on its diamond mines.