Apple's partner, GT Advanced Technologies uses molten alumina to make sapphire glass for iPhone 6

According to recent reports, Apple has been pushing to make its sapphire production operational and running in time for the release of its next flagship phone.

Apple has started including sapphire technology into its devices but not as full scale as a sapphire screen. The camera of the iPhone 5s features a sapphire glass protection. Likewise, the new home button/fingerprint scanner on the iPhone 5s sports sapphire glass.

Although it is called a glass, the sapphire glass is not entirely a glass. It refers to a single crystal made of transparent sapphire. Sapphire is manufactured synthetically. The process involves dipping a little piece of sapphire or seed crystal in molten alumina (Al2O3). After dipping, the seed crystal is drawn upwards. This creates extremely long carrot-shaped crystals known as boules. The crystals are sliced, molded and polished as needed. The process is expensive. But Apple's recent partner, GT Advanced Technologies, may have just discovered a way to produce the materials and bring it commercially.

According to an article from MIT Technology Review, "GT is also cutting the cost of sapphire manufacturing by following the strategy that it used over the last several years to reduce the cost of making crystalline silicon for solar cells."

"To make the sapphire, aluminum oxide is melted down in a specialized furnace and then allowed to slowly cool to form a large crystal. That crystal is then cut with a diamond-coated wire saw. GT designs its furnaces so that they can be cheaply upgraded to make ever larger crystals as the technology improves, allowing customers to increase production without buying new equipment." the article from MIT Technology Review added.