U.S. glassmaker Corning Inc. presented Gorilla Glass 4 on Thursday, the latest edition of its leading protective glass cover for smartphones and tablets.

CNET reports that the company claims the new cover is twice as tough as Gorilla Glass 3.

Corning is confident its fourth-generation smartphone display glass will protect smartphone screens from cracks, but the company is far from finished in its product development.

"Today, glass still breaks, and glass still scratches," Dave Velasquez, director of marketing and commercial operations for Gorilla Glass, told Bloomberg Businessweek. "Until those things go to zero, the customer is not going to be happy."

Corning researchers spent thousands of hours studying numerous broken devices and discovered that "sharp contact" damage was 70 percent responsible for broken screens. Sharp contact involves dropping the phone on a rough surface, such as concrete. Phone screens shattered less when dropped onto smooth surfaces, such as marble.

In drop tests using 180-grit sandpaper, Gorilla Glass 4 was twice more likely than Gorilla Glass 3 to survive a 1-meter drop onto the sandpaper. When the cover glass fell face down on the surface, Gorilla Glass 4 succeeded 80 percent of the time.

"The cover glass is going to break less often, particularly on a rough surface," Velasquez said.

What exactly makes Gorilla Glass 4 so tough? The product is made of alkali-aluminosilicate sheet toughened glass. Velasquez said it is a new composition of the material but declined to give details.

Corning's next goal is to mold Gorilla Glass into curved displays that protect and enlarge the area of usable screen, according to Bloomberg Businessweek. Forbes reports that Samsung has already released the Galaxy Round overseas and Apple is rumored to be working on curved glass iPhones.