Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Tiffany (NYSE: TIF) fell more than 11% in early trading before closing down about 7% on fears that weakening demand in China could affect revenue and earnings, Reuters reports.

So what: A Morningstar analyst quoted by the wire service said that luxury sales to consumers in the Sino superpower may not be holding up as well as some had thought. Shares of Coach (NYSE: COH) and Ralph Lauren (NYSE: RL) also fell on the news.

Now what: But Tiffany may suffer more than most. Reuters says the jeweler saw Asia sales outside of Japan rise 45% in its latest quarter. Cutting off that spigot would mean crimping gains for a stock that, priced at more than 20 times earnings, needs growth to justify its valuation. Do you agree? Would you buy shares of Tiffany at these levels? Please weigh in using the comments box below.

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Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. He didn't own shares in any of the companies mentioned in this article at the time of publication. Check out Tim's portfolio holdings and Foolish writings, or connect with him on Google+ or Twitter, where he goes by @milehighfool. You can also get his insights delivered directly to your RSS reader.

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