BARCENA—Sapphire could someday be used in some smartphone displays instead of the toughened Gorilla Glass popular today.

In this case, however, it would be man-made sapphire, not the rare blue gemstone that is taken from ground used in jewelry.

GT Advanced Technologies hopes that a new furnace it makes to produce industrial sapphire from the plentiful raw material corundum will help lower its cost enough to convince makers of smartphones ruggedized devices to switch to sapphire instead of glass. One furnace can cost between $300,000 $400,000.

Today, smartphone glass costs about $1 per diagonal inch in a smartphone, compared to $3 to $4 per inch for sapphire, said GT’s ff Nestel-tt, director of marketing communications.

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That cost could drop dramatically in the next two years, as GT’s Advanced Sapphire Furnace is used to produce manufactured sapphire, he said. The furnace heats to 2200 degrees Celsius, helping to create the huge sapphire boule after 16 days of curing. The boule can then be sliced into thin display material.

Sapphire is already used in smartphone camera lenses because it is so tough, Nestel-tt said in an interview at Mobile rld Congress (M) here. In a demonstration, he tried to scratch a thin slice of sapphire mounted atop an ione 5 display with a sharp piece of concrete. After several seconds of scraping, tapping even pounding, the concrete actually flaked off into tiny particles since the sapphire cover was actually harder.

Sapphire is the second hardest material in the world behind diamond, is harder than glass. On the Mohs mineral hardness scale, diamond gets a 10, sapphire a 9 glass (made from quartz) a 7.

Nestel-tt also showed how his concrete rock left a pretty significant scratch on a separate display made of toughened glass. The problem with too many scratches on a smartphone display is that they can weaken the display, eventually breaking it up entirely when dropped.

Sapphire also offers optical purity is used to produce chips used in D lights, GT officials said.

GT is just starting its campaign to promote the furnace, Nestel-tt said. “The cost has come down to a point that we feel there’s a broader opportunity to take sapphire to new market opportunities for device covers touchscreens,” he said.