Apple has invested $700 million in producing synthetic sapphire, one of the hardest minerals on Earth, for the newest iPhone’s display screens. Sapphire is expensive to produce, but the material does not crack or scratch as easily as the glass currently used in iPhones. Apple and GT Advanced Technologies have opened a facility in Arizona to produce the new material. The facility’s ability to meet the demand will determine whether Apple rolls out an iPhone with a sapphire screen.

Apple is betting that synthetic sapphire will protect its popular smartphone better than the Gorilla Glass displays of previous iPhones. Because of the material’s hardness, sapphire is nearly scratch-resistant and it is more difficult to crack the screen. It also withstands higher temperatures and it will not corrode.

Sapphire is already used in airplane windows and armored vehicles. And Apple already uses sapphire sparingly to protect the camera lens and fingerprint reader on its iPhones.

Sapphire is used sparingly because the material is costly to produce. While a Gorilla Glass screen costs about $3 to produce, a sapphire screen will cost about $16. If Apple is able to produce enough of the material, the company is expected to debut the new feature in the more expensive models of the new iPhone. While Apple may save some money in warranty expenses, the savings would not likely offset the component’s cost.

The 1.4-million-square-foot facility in Mesa, Arizona has started transitioning to high-volume production, and the first sapphire screens are expected to roll out this month.

“At full capacity, the plant will produce twice as much sapphire as the current output from the nearly 100 manufacturers world-wide, says Eric Virey, a senior analyst at French research firm Yole Développement,” reports The Wall Street Journal.

It is still unclear as to how well the sapphire will perform as a phone display. The screen could still break because the material’s strength depends on its thickness and cut. In fact, in some tests, Gorilla Glass was more durable than sapphire when the screens were dropped from different heights. Also, a sapphire screen will make the phone heavier and perhaps harder to view in sunlight due to the amount of light that reflects off the material.

A few smartphone manufacturers already produce phones with sapphire screens. The Brigadier phone by Japan’s Kyocera Corp. is marketed at virtually scratchproof. Vertu Corp. in Britain also makes expensive phones with sapphire screens.