While sapphire glass is very expensive, Apple does use the material to cover the camera on the iPhone. On the Apple iPhone 5s, sapphire glass protects the fingerprint scanner that is embedded in the home button for Touch ID. With the scanner, the tiniest scratch can affect the results, which is why Apple has resorted to employing the material on the feature. But thus far, Apple has limited its use of sapphire glass to small pieces of the material.
Sapphire glass can be currently found on some luxury handsets, but the cost of the material is preventing it from being more widely used. Consider that the price of a large phone display made of Gorilla Glass is estimated to cost $3. A sapphire glass display of the same size would probably run about $30. LG took a look at using sapphire glass, and rejected the idea, because of the cost of obtaining the material.
And despite some recent videos claiming to show how unbreakable the alleged sapphire glass front panel of the iPhone 6 is, a representative from a major handset manufacturer says that the larger the size of a sapphire screen, the more brittle it is. And outside of Apple, no manufacturer will be able to procure a large enough supply of the stuff to not worry about inventory disruptions.
Thus, for now, Corning Gorilla Glass remains the material of choice for most smartphone displays. As for Apple and the iPhone, we will have to wait until the phone is unveiled, most likely in September, to see if the gang in Cupertino decides to make the switch to sapphire. If they do, it most likely will be Apple bearing the brunt of the additional cost of the material.