There's speculation that this year's forthcoming iPhone 6 might do away with the traditional Gorilla Glass screen and incorporate sapphire glass to allow for solar charging.
The rumors come from a Seeking Alpha analyst, quoted in Forbes, who connected the dots among several points of evidence.
First, Apple's new manufacturing plant in Mesa, Ariz., is being used to produce sapphire glass after a $578 million partnership with GT Advanced Technologies last year. Earlier in 2013, Apple posted and filled a job listing for a mobile device engineer with solar industry experience. Also last year, Apple patented a power management system for iOS and Mac device operation that uses sunlight.
Sapphire glass is about three times as durable as Corning's Gorilla Glass, the current screen material of choice for smartphones, but comes with about five times the price tag. Still, Forbes said GT has been able to drive down the cost of sapphire glass per iPhone screen from $13-$18 to $3-$5, putting it in competitive range with the $3 Gorilla Glass.
Apple's potential adoption of sapphire glass could be a move to compete with other companies like Samsung and LG, who offer more durable curved displays on some smartphones, a move Apple has yet to try.
The analyst said that more than 100 iPhone prototypes have been assembled with sapphire glass screens, suggesting Apple is at least testing the material's potential. A sapphire glass screen could be embedded with solar cells to allow for increased battery life through solar charging. If this proves true, the iPhone 6 may be even thinner than previous models due to lower battery weight.