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For Gorilla Glass testers, life is a daily grind (and scratch and drop...)

At Corning's Gorilla Glass testing labs, the glassmaker that fronts Apple's iPhone tried to show that rival sapphire crystal isn't all it's cracked up to be.

Ben Fox Rubin Former senior reporter
Ben Fox Rubin was a senior reporter for CNET News in Manhattan, reporting on Amazon, e-commerce and mobile payments. He previously worked as a reporter for The Wall Street Journal and got his start at newspapers in New York, Connecticut and Massachusetts.
Ben Fox Rubin
9 min read
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Inside the labs, where a Corning engineer performs a puncture test on glass. Ben Fox Rubin/CNET

PAINTED POST, N.Y. -- Using extra-fine sandpaper (320 grit, to be exact), Corning scientist Kevin Reiman lightly rubbed the surface of a small, thin square of transparent sapphire crystal.

Synthetic sapphire, a material second only to diamonds in hardness, has been the talk of the tech industry this year as a potential replacement to the glass that now covers smartphone screens. The sapphire piece Reiman held didn't scratch. Not one bit.

The next generation of Gorilla Glass will be revealed next month. Ben Fox Rubin/CNET

But then he placed the 0.5-millimeter-thick sample on a table and pressed against its surface with the pink eraser on the back of a pencil. With a dull pop, the sapphire broke into pieces with as much exertion as Reiman may have used to push a doorbell.

"You can't see the damage, but its strength is gone," Corning executive Jaymin Amin later explained. "Its retained strength is very, very poor."

The demonstration was part of my visit to Corning this month, where the 163-year-old glassmaker -- they built the first light bulbs for Thomas Edison -- offered a rare look inside its reliability and testing labs for Gorilla Glass. The hardened glass released seven years ago now fronts 2.7 billion electronic devices, including Apple's iPhone and Samsung's Galaxy Note Edge. While showing the torture testing that goes into making Gorilla, Corning's scientists also presented for the first time a handful of in-person demonstrations that compare its glass to sapphire -- part of Corning's effort to move the conversation about sapphire away from its scratch resistance and toward its brittleness.

With the sandpaper test, Gorilla Glass did get scratched -- a lot. But a pencil eraser failed to break it.

Its durability aside, Corning's Gorilla Glass is under even more pressure to stay ahead of the market. Mobile devices are updated and redesigned faster than ever, forcing Corning to speed its research process. The company has also had to contend with claims that Apple -- its most prominent customer -- might swap out Gorilla Glass in its iPhone for sapphire, a move that seemed likely after Apple signed a $578 million deal last year to make a massive amount of sapphire. In a surprise turn, Apple's supplier -- GT Advanced Technologies -- filed for bankruptcy protection this month and will shut down its sapphire production.

The stumble may buy Corning more time to improve its products -- that is, until another company or material tries to knock Gorilla Glass off its throne.

Watch this: Meet the people who torture Gorilla Glass for a living

Corning has reason to be defensive about Gorilla Glass. The business now generates roughly $1 billion annual sales for the company (out of total sales of $7.8 billion last year) since it was released as the display cover for Apple's original iPhone smartphone in 2007. The material is now used in a majority of smartphones and tablets from just about every major device manufacturer.

Corning, based in the 11,000-population upstate New York city it's named after, said Tuesday it plans to unveil its fourth-generation Gorilla Glass on November 20, claiming it will offer "dramatically improved" performance.

Corning's main business of making LCD displays for televisions has been challenged by falling prices (the LCD business accounts for about 40 percent of sales). So, a lot of the company's future expansion rests on Gorilla and Corning's plan to capitalize on the rapid growth of smartphones and tablets, Oppenheimer analyst Andrew Uerkwitz said. "There's not a single growth driver equal to Gorilla Glass," he added.

Corning's expert glass-breakers

At work bending glass at the labs. Ben Fox Rubin/CNET

Far from Apple's slick, high-wattage product launch events in California, the iPhone's display glass is developed in an unassuming, blue and gray building on a quiet country road across from an unkempt cornfield. The low-standing structure in Painted Post, N.Y., houses the Gorilla Glass reliability and testing labs, where a team of engineers spends much of their day dropping, bending, shattering and scratching the material.

"We primarily break glass. It's our job," said a smiling Jon Pesansky, who runs the labs.

Much of the space is off limits to other Corning personnel, since it's used to test experimental recipes of Gorilla Glass and to collaborate with smartphone makers on prototype devices. Visitors are usually required to sign a confidentiality agreement when entering and I was told not to take wide photographs of the labs, so Corning's competitors couldn't ascertain the size of the space.

The group visiting included me and a team from electronics repair chain uBreakiFix. We put on safety glasses, walked into a restricted corridor and soon entered one of the main labs, which -- despite all the secretiveness -- looks a lot like shop class. There were large testing machines set in stations along bare white walls, with a handful of researchers there to present their torture devices.

Gorilla Glass gets a workout. Ben Fox Rubin/CNET

Using the machines, the workers took turns bending, puncturing and scratching the glass, repeatedly emphasizing the point that Gorilla Glass -- unlike sapphire -- retains its strength even after being damaged. It may scratch, but it doesn't break easily. During my visit, I tried to break a thin piece of Gorilla Glass with a pencil-sized metal rod, putting most of my weight into the effort. My hand shook and reddened, but I couldn't make a dent in the glass.

One worker used a machine to drop a metal ball on the glass from varying heights. Another dropped a dummy smartphone with its outer shell made almost entirely of glass onto a marble surface. I asked why Corning was using a nearly all-glass phone, and one worker explained that they like to test out new design concepts before handset makers come to them with the idea, so they can stay one step ahead of a fast-moving industry.

"Part of what we're doing is looking at the real details of how things break in the field and then bringing that back into the laboratory to generate new tests," Reiman said, "so we can evaluate the damage resistance of glass better, so we can design better glass."

Apple finds a tough partner

Corning's Jaymin Amin. Ben Fox Rubin/CNET

When Apple was first developing the iPhone, it tested out plastic as the display screen, like with the iPod music player, but found that it scratched too much and lacked style. Soda-lime glass, which is used for windowpanes and bottles, wasn't strong enough. "We told them absolutely we can make a better glass," said Amin, an affable Brit who heads up Gorilla's technology development.

During an early meeting, Apple CEO Steve Jobs told Corning CEO Wendell Weeks he wanted as much of the material as could be made within six months for the iPhone's first launch, according to Walter Isaacson's biography of Jobs. Weeks responded that his company didn't have the capacity to complete the project. "Yes, you can do it," Jobs told him. "Get your mind around it. You can do it."

An Apple representative didn't respond to a request for comment.

Corning, which got its start making kerosene-lamp globes and colored signal lenses for railroad companies, used a hardened glass it developed in the 1960s as the basis for Gorilla Glass. That precursor material, called Chemcor, was marketed for car windshields and prison windows, though it failed to sell.

Decades later in the new market of mobile devices, Gorilla Glass became a hit, in large part because of Apple's endorsement. The material has been used in every iPhone, including the new iPhone 6 and 6 Plus, as well as dozens of laptops, smartwatches and tablets from Samsung, LG, Acer, Dell and Motorola.

Gorilla gets its strength by a manufacturing process that replaces the glass' sodium ions with larger potassium ions, creating more compression at the material's surface. It's something like replacing tennis balls with softballs inside a frame. The effect is a more scratch- and damage-resistant glass, despite the fact that intrinsically glass isn't all that strong.

As of last year, Gorilla Glass held more than 80 percent of the hardened cover glass market it helped create, according to Bernstein Research. Japan-based Asahi Glass' 3-year-old Dragontrail is growing its market share but remains a distant competitor. Nippon Electric Glass of Japan, Schott of Germany and KMTC of China have introduced similar cover glasses though haven't gained much traction.

Gorilla contributed just 15 percent of Corning's overall revenue last year, with the company's businesses spanning TV displays, fiber optics and research lab equipment. But, Gorilla Glass has been the leading growth driver for the company, as Corning works to expand the material's use for car windows and displays (one of Chemcor's original markets), elevator walls and kitchen backsplashes.

The company has dominated the market thanks, in part, to Gorilla Glass becoming one of Corning's most recognizable brands. It's now synonymous with tough glass -- a feature manufacturers use to market their mobile devices.

Kevin Reiman, at his fractography post, shows off a magnified cross-section of glass. Ben Fox Rubin/CNET

Back at the testing lab, Reiman sat at his desk, where he provided a tutorial in his area of specialty -- fractography, or the study of fractured surfaces. He propped up a shard of glass using a piece of gray putty, placing it under a large microscope connected to a computer monitor. Looking at a magnified cross-section of the shard on the computer screen, he searched for the "fracture origin" -- the smoking gun that initiated the break. "I happen to think these are beautiful," he said, pointing to a close-up of the glass shard.

A piece of soda-lime glass under Reiman's microscope. Ben Fox Rubin/CNET

He takes samples from devices sent by handset makers, pieces used in Corning's lab tests or busted phones brought by co-workers ("If we've got a phone in the family that's broken, we give it to Kevin," Amin said). Reiman then uses each break to learn more about the glass so he can try to make the next Gorilla Glass a little better.

"It's like detective work, looking for clues, looking for evidence, piecing it together and putting the story together," Reiman said. "It's a lot like CSI, in a way, because you're letting the glass tell the story of how did it break."

Gorilla's next step forward

The reliability and testing team's work is part of Corning's broader research and development engine. The company spends hundreds of millions of dollars a year and employs about 1,700 scientists at its headquarters to better understand glass and other materials. It's all that R&D that has helped Gorilla Glass maintain its lead in the market, said Oppenheimer's Uerkwitz, who added that Corning's rivals spend far less in R&D each year to catch up to Corning's latest innovation.

Although Corning's executives say they see a strong future for its glass in mobile devices, some industry analysts predict that down the road more smartphone makers will use sapphire as display covers. A handful of niche phones already do, including the heavy-duty Kyocera Brigadier and Vertu Signature Touch, which starts at $10,800. Apple also uses the material in newer iPhone models to cover the device's home button and back-camera lens. "I think sapphire will be adopted in high volume sooner or later," said Pierre Maccagno, an analyst at Dougherty & Co. who holds a Ph.D. in material science. The reason, says Maccagno: sapphire is a "superior" material to Gorilla.

Corning's Amin agreed that sapphire had some impressive qualities but disputed that it would ever become mainstream. He said it was too brittle to be used in most smartphones, even as a laminate atop Gorilla.

Corning's headquarters building in Corning, NY. Ben Fox Rubin/CNET

Sitting in the Corning headquarters dining hall, which features large windows overlooking the Chemung River, Jeffrey Evenson, the company's operations chief of staff, discussed the future of Gorilla Glass. He told me a main focus will be making it even stronger, so it can survive the daily scrapes, drops and bumps a smartphone gets in the real world.

On top of that, Corning is looking into glass that reflects less light, repels water (to avoid phone shortages in the sink) and fends off oil (to prevent fingerprints on the screen). Corning can make Gorilla Glass thinner than a dollar bill, so it appears the company is looking to add new features to the next generations, since Gorilla can't get much thinner. Evenson conceded that it will be a challenge to balance all those capabilities into one piece of glass, but added, "We think we can definitely offer improvements on multiple dimensions at once."

A piece of Corning's new curved-edge Gorilla Glass. Ben Fox Rubin/CNET

In a hint at what could be coming next, earlier in the day Amin showed off a sleek glass display with curved edges all around, offering a potential wrap-around look for a smartphone. Although the display is curved, Amin said the company was able to make it just as transparent and durable as flat Gorilla sheets. "I think it has exciting potential," Evenson said. "We're looking forward to working with customers on it."

But before the new design can hit the market, it will first have to make it through Corning's torture lab.