(Adds details throughout on stocks and sectors, updates prices)
* TSX down 40.77 points, or 0.28 percent, to 14,724
* Four of the TSX's 10 main groups lower
TORONTO, Aug 24 (Reuters) - Canada's main stock index fell on Wednesday as lower metal and oil prices weighed on resource stocks, offsetting gains for financials after Royal Bank of Canada reported better-than-expected earnings.
The materials group, which includes precious and base metals miners and fertilizer companies, lost 2.9 percent.
Copper prices fell to eight-week lows as rising inventories in Asian warehouses fueled fears about weaker demand to come in top consumer China, while spot gold fell 0.9 percent ahead of a speech by Federal Reserve Chair Janet Yellen on Friday which will be closely watched for further clues on U.S. interest rate policy.
Barrick Gold Corp fell 5.7 percent to C$24.46, while Silver Wheaton was down nearly 5 percent at C$34.99.
Energy stocks dipped 0.1 percent as oil fell.
U.S. crude prices were down 1.1 percent to $47.59 a barrel as data pointing to a potential build in domestic crude stockpiles offset speculation of an output freeze by major oil producers.
At 10:17 a.m. EDT (1417 GMT), the Toronto Stock Exchange's S&P/TSX composite index fell 40.77 points, or 0.28 percent, to 14,724.
On Tuesday, the index had touched a one-week high at 14,796.56.
Just four of the index's 10 main groups were lower on Wednesday, including a 0.3 percent dip in telecommunication stocks.
Financials rose 0.4 percent, led by banks stocks after forecast-beating earnings from Bank of Montreal on Tuesday and Royal Bank of Canada on Wednesday.
Royal Bank of Canada reported slightly higher-than-expected quarterly results after rising oil prices allowed it to set aside less money to cover energy companies' bad loans.
Its shares rose 0.1 percent to C$82.31, while Bank of Nova Scotia gained 1.2 percent to C$68.13. (Reporting by Fergal Smith; Editing by Meredith Mazzilli)