Luxury jeweler Tiffany & Co. (NYSE:TIF) and its mall-based peer Signet Jewelers (NYSE:SIG) report second-quarter results Thursday, but how will China's economic woes and the Apple (NASDAQ:AAPL) Watch impact earnings? Wall Street expects Tiffany's Q2 per-share earnings to decline 5% to 91 cents and revenue to edge up less than 1% to $1 billion, as deteriorating conditions in China weigh on results. "Relative to SIG, we maintain a more cautious 2H15 outlook for TIF as we believe recent (yuan) devaluation may be a revenue headwind," given 12%-13% sales penetration in China and fewer Chinese tourists spending money at Tiffany, Cowen & Co. analyst Oliver Chen wrote last week. He rates Tiffany outperform with a 103 price target. View Enlarged Image Shares were down 3.5% in the stock market today. Signet shares were off 2.2%. But Oppenheimer analyst Brian Nagel remains optimistic. "Tiffany demonstrates time and again that sales trends at its... More