For Gorilla Glass, Corning narrows down the number of compositions to a few dozen, does more melting, then picks two or three candidates to test. Corning stock fell over 4% on Tuesday morning after the company reported a weaker-than-expected outlook for the current quarter, blaming slow smartphone glass sales. Corning makes a variety of different components and supplies many of the top electronics companies, like Samsung and Apple, which reports earnings this week amid concern over slowing consumer electronics sales. But there is optimism that slowing electronics sales won't hurt the high-end of the market as much as less expensive devices. In the quarter ending in September, Corning saw smartphone unit sales decline 14% on an annual basis, and tablet and notebook demand fall 17%, Corning CEO Wendell Weeks said on an earnings call.

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