* TSX drops 1.6 percent to 11,094.31
* Potash Corp leads decliners for second day
* Economic data fails to calm "spooked" investors (Adds details)
By Ka Yan Ng
TORONTO, Jan 29 (Reuters) - Toronto's main stock index sank 1.6 percent on Friday to close at its lowest level in three months, pressured by weak commodity prices after stronger than expected U.S. economic data sparked a rally in the greenback.
The heavyweight energy and materials sectors were among two of the big drags on the index, down 1.2 percent and 3.5 percent respectively, as prices for crude oil and gold drove lower. [O/R] [GOL/]
Fertilizer producer Potash Corp (POT.TO) slumped for a second straight session, down 4.8 percent at C$105.92.
Royal Bank of Canada (RY.TO) was the top heavyweight decliner, falling 2.24 percent to C$52.28.
The Toronto Stock Exchange's S&P/TSX composite index .GSPTSE finished down 179.89 points, or 1.6 percent at 11,094.31. Eight of the index's 10 main groups were lower, with five of them off more than 1 percent each.
Unexpectedly strong fourth-quarter economic growth in the United States, and healthy November gains in Canada, failed to lift investors' spirits, which have been deflated by recent policy moves by China and the White House's plan to rein in risk-taking by big banks. [ID:nN28246399] [ID:nN29201456]
"The problem is that, at this point the economic numbers and corporate earnings have taken a back seat to some of the concerns that have manifested themselves in recent weeks," said Elvis Picardo, analyst and strategist at Global Securities in Vancouver.
"Investors are spooked." (Reporting by Ka Yan Ng; editing by Rob Wilson)