In a demonstration of just how much Wall Street keeps an eye to the East, markets logged their worst day of the year on Monday as China's GDP slowed more than expected. Although the S&P 500 Index (^GSPC 0.02%) fell 2.3%, it was a small decline when compared to the day's three biggest laggards.

Freeport-McMoRan Copper & Gold (FCX 0.52%) ended as the worst performer in the entire 500 stock index, as shares shed 8.3%. It should come as no surprise on a day that saw gold prices post their largest single-day decline in more than 30 years. Gold ended at two-year lows, closing down more than 9%. On record-high trading, the precious metal has fallen nearly 30% since its all-time highs. 

Registering its second straight day as one of the day's 3 Worst Stocks, Cliffs Natural Resources (CLF -1.24%) also lost 8.3%, as energy stocks, materials, and industrials got hit particularly hard Monday. It's now down nearly 55% in 2013 alone, hitting a 52-week low during trading today. The company is set to report earnings next Wednesday. Investors seem to be sending the message today that the coal miner may suffer from weaker global demand.

China's new president, Xi Jinping, said earlier in the month that the country's days of "ultra-high speed growth" were through. Today offered some proof of that sentiment, as industrial production slowed from the first quarter of last year. As a result, industrial stocks took a major hit, and construction services company Fluor (FLR -0.17%) ended the day as the third-worst performer, slipping 8.2%. Today's trading volume -- more than 15 million shares changed hands -- was more than 10 times its daily average.