Now let me get this straight: There's a potential Category Four hurricane eyeing the Gulf of Mexico, and crude oil prices slid about $2 a barrel on Thursday alone. Isn't it supposed to go the other way?

Typically it is, but try to find a commodity that wasn't down meaningfully amid the roller coaster swings that saw the Dow Jones Industrial Average fall by 300 points, only to finish at a much less daunting and death-defying 15-point decline. But wait just a minute, are we taking about equities or commodities?

The answer is both. Fortunately or unfortunately, there's an inextricable relationship between them, which has clobbered a host of companies of late. ExxonMobil's (NYSE:XOM) shares were down about 1.25% on Thursday on the lower crude prices, while Schlumberger (NYSE:SLB), the leader of the oilfield services pack, was hit to the tune of 1.6%.

But the real walking wounded of late, as investors have diverted money from commodities positions to cover other losses or to meet margin calls, have been the mining companies. Shares of copper and gold producer Freeport McMoRan (NYSE:FCX), for instance, have given up nearly 11% in just the past week as copper prices have slid steadily. Indeed, on Thursday alone, prices of the metal fell by pretty much the same percentage surrendered by Freeport shares.

Along with Freeport, Australian mining giant BHP Billiton (NYSE:BHP) has slid about 6% in the past week, and Billiton's only slightly smaller Anglo-Australian mining compadre Rio Tinto (NYSE:RTP) has seen its shares fall by about 19% in the past month. In fairness, however, Rio Tinto's planned acquisition of Canadian aluminum producer Alcan (NYSE:AL) may have exacerbated its own slide.

So now let me crawl tenuously out on a limb: With specific regard to Freeport, an incredibly solid company has been cuffed around by the market to the extent that its forward P/E is now less than 8 times. This, despite a PEG ratio (the expected growth rate over five years divided by the P/E, such that lower numbers are better, and scores below 1.0 are terrific) of less than 0.8.

Despite the shares' slide, I'd suggest that Fools avoid the company until general market conditions stabilize and thereby permit commodities prices to grab. When that occurs, however, if you're in search of quality -- albeit with an element of commodity-induced volatility -- you'd be wise to look very hard at Freeport McMoRan.

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Fool contributor David Lee Smith doesn't own a share in any of the companies mentioned. He does welcome your emails. The Motley Fool has a disclosure policy.