* TSX down 55.87 pts, or 0.5 pct, to 11,432.66 * Energy, mining shares lead losses * Greek turmoil weighs on markets * Losses pared on strong German, Canadian data By Jon Cook TORONTO, May 15 (Reuters) - Canada's main stock index hit a seven-month low on Tuesday as energy and mining shares fell on persistent worries about Greece and its impact on other euro-zone nations, outweighing upbeat data on German economic growth and solid Canadian home sales. Seven of Canada's 10 main sectors were lower. The materials and energy groups, which comprise nearly half the overall weight of the main index, both slid 0.9 percent. "The flavor of the day is not to own resources, not to own risk stocks," said Michael Simpson, senior portfolio manager at Sentry Select Capital Corp. Oil and gas firms fell despite a rise in crude oil prices, as better-than-forecast growth in Germany's gross domestic product in the first quarter pulled the euro zone back from the brink of recession. "It confirms the entire euro zone is not going into recession and the lead member is still strong, but there is still concern about the peripheral nations," said Simpson. Losses were led by Canadian Natural Resources, which fell 1.4 percent to C$29.83 a day after the Alberta government charged the oil and gas producer with releasing poisonous hydrogen sulfide gas from its Horizon oil sands plant two years ago and failing to report the incident. Suncor Energy, Canada's largest oil producer, dropped 0.5 percent to C$27.85. Materials sector losses were led by miners Barrick Gold , which fell 0.7 percent to C$36.38, and Teck Resources , down 1.2 percent to C$31.33. At 11:30 a.m. (1530 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 55.87 points, or 0.5 percent, to 11,432.66. It touched a session low at 11,406.45, its lowest level since Oct. 5. The index was on track to finish down for the ninth time in its last 10 sessions; it has fallen more than 7 percent so far this month. Financial shares slumped 0.3 percent on Tuesday after Greek officials said they will hold a new election, prolonging a political crisis that threatens to push the country closer to bankruptcy and exit from the euro. "Greece at the moment appears ungovernable," said Simpson. "The official statement is that Greece is going to stay in the euro, but if that is not the case the world economy can still go on." Toronto-Dominion Bank was the most influential decliner, down 0.5 percent to C$79.55. Top insurer Manulife Financial fell 0.5 percent to C$11.94. Helping counter the negative market tone was Canadian housing data on Tuesday that showed existing home sales edged up 0.8 percent in April from March and were up a strong 11.5 percent from a year earlier. U.S. data on Tuesday was mixed, with weak retail sales in April offset by a better-than-expected increase in factory activity in New York state.