* TSX falls 122.45 points, or 0.91 percent, to 13,349.77 * Eight of the 10 main index sectors decline * Gold miners drop 2.6 percent * Couche-Tard jumps after reporting results By John Tilak TORONTO, Nov 26 (Reuters) - Canada's main stock index dropped to its lowest in more than a week on Tuesday as volatile commodity prices hit natural resource stocks, with gold miners bearing the brunt of a widespread selloff. The drop, the second straight for the Toronto stock market's benchmark index, was its steepest percentage drop in more than two months. Uncertainty about the future of the U.S. Federal Reserve's monetary stimulus plans and sluggish physical demand were a drag on the price of gold, which fueled the decline in gold mining shares. Data showing that permits for U.S. home construction hit a near 5-1/2 year high in October and that prices for single-family homes in the United States soared in September failed to inject much enthusiasm into the market. Meanwhile, the Iran-big power nuclear agreement left investors perplexed about the direction of commodity prices. "We've been struggling to gain any traction this week," said Elvis Picardo, strategist and vice president of research at Global Securities in Vancouver. "Investors are taking the news from Iran as one more reason not to buy Canada." "The money is gravitating towards where it is performing best, and that is obviously the U.S. equity space," he added. Though the Canadian market is up about 8 percent this year, the gains pale in comparison to the advances made by U.S. stocks. The Toronto Stock Exchange's S&P/TSX composite index closed down 122.45 points, or 0.91 percent, at 13,349.77 on Tuesday. By contrast, the S&P 500 was little changed. Eight of the 10 main sectors on the Toronto index were in the red. Shares of financial companies fell 1.1 percent, with Royal Bank of Canada down 1.4 percent at C$70.51 and Bank of Nova Scotia dropping 1.6 percent to C$65.42. The two stocks had the biggest negative influence on the market. Gold producers gave back 2.6 percent. Goldcorp Inc shed 2.9 percent to C$23.51, and Kinross Gold Corp fell 2 percent to C$4.87. The index's gold-mining sector has lost close to half its value this year. In company news, Rogers Communications Inc said it signed a landmark C$5.2 billion ($4.9 billion) deal to broadcast National Hockey League games in Canada for the next 12 years. The stock, down 1.2 percent at C$46.23, fell with the broader market. Alimentation Couche-Tard jumped almost 3 percent to C$76.17 after the convenience store chain reported a 27 percent rise in quarterly profit, driven by higher gasoline margins and acquisitions.