Apple has a tendency to fixate on a single feature with each new product release. For the iPhone 4S, it was Siri that received the lion's share of attention, and the for the iPhone 5S, Apple spent a lot of time talking about Touch ID, a fingerprint recognition system built into the home button. When the unannounced iPhone 6 comes to town, there's a good chance Apple will tout its seriously rugged display.
There's a new video floating around demonstrating the extreme durability of the alleged iPhone 6's sapphire crystal display, which is reportedly replacing Corning's Gorilla Glass. In the video, Marques Brownlee, host of the YouTube channel MKBHD, tries scratching the display with a knife and then a set of keys before returning to the knife for a series of jabs. Not a single scratch emerged.
Brownlee also tried bending the display. He was a bit cautious at first, but quickly discovered it was unlikely he'd be able to break the display with anything less than Herculean strength. It's a truly remarkable demonstration, and according to Brownlee, there are no visual quality sacrifices to achieve that level of durability. In fact, sapphire crystal is the same material that protects the camera lens on the iPhone 5S, along with the Touch ID-enabled home button.
As for size, the display in the video measures 4.7 inches. We've heard rumors that Apple might release two versions of the iPhone 6, one with the aforementioned 4.7-inch display and a second that creeps into phablet territory with a 5.5-inch screen.