July 9 (Reuters) - Canada's main stock index fell for the third straight session on Tuesday, with the materials sector leading the declines as gold prices eased to a one-week low.
* At 9:34 a.m. ET (1334 GMT), the Toronto Stock Exchange's S&P/TSX Composite index was down 31.8 points, or 0.19%, at 16,431.15.
* The materials sector, which includes precious and base metals miners and fertilizer companies, lost 0.4%, the most on the TSX.
* Gold prices dropped below $1,400 as the dollar rallied on expectations of a less dovish U.S. Federal Reserve ahead of testimony from the chairman of the central bank.
* The financials sector slipped 0.3%. The industrials sector fell 0.1%.
* Investors are also looking ahead for a key interest rate announcement by the Bank of Canada on Wednesday, where the central bank is widely expected to keep rates on hold at least through this year.
* On the TSX, 79 issues were higher, while 138 issues declined for a 1.75-to-1 ratio to the downside, with 6.87 million shares traded.
* The biggest percentage gainers on the TSX were Richelieu Hardware Ltd, which jumped 1.2% followed by shares of Genworth MI Canada, which rose 1%.
* Canntrust Holdings fell 4.4%, the most on the TSX, followed by shares of First Quantum Minerals, down 3.9%.
* The most heavily traded shares by volume were Canntrust and Trevali Mining.
* The TSX posted one new 52-week high and two new lows.
* Across all Canadian issues there were five new 52-week highs and five new lows, with total volume of 13.42 million shares. (Reporting by Shreyashi Sanyal in Bengaluru; Editing by Arun Koyyur)