Rumor has it that Apple's upcoming iPhone 6 will feature a larger screen made of sapphire glass. Some wonder whether or not this is a practical possibility, but according to new reports, Apple just ordered enough sapphire crystal to make hundreds of millions of iPhones.

The rumor that the iPhone 6's screen will feature sapphire glass came when CNBC reported that Apple made a $578 million deal with GT Advanced Technologies, which specializes in producing sapphire substrate. According to various analysts, however, an iPhone, or any other large smartphone enhanced with a sapphire glass screen, would be too expensive for anyone to be interested.

9to5Mac, on the other hand, reports that Apple just acquired enough sapphire crystal furnaces to make between 100 million and 200 million 5-inch iPhone screens. The blog cites "new documents" and information from Matt Margolis, an analyst, as their source.

"...it appears that Apple is planning to build sapphire-crystal displays for future iPhones," the blog said. "This is opposed to this facility building sapphire components for future Apple Touch ID fingerprint readers and caps for camera sensors. The proof that GT Advanced is preparing to manufacture sapphire for displays comes from import/export records ... GT Advanced has ordered Intego Sirius Sapphire Display Inspection Tool components."

One of the documents obtained by the blog says that sapphire glass can be made more affordable by "lowering manufacturing and fabrications costs of sapphire," which GT Advanced Technologies is doing.

Others still say the feature is not likely. They suggest that sapphire glass will probably be used for the iPhone 6's home button and camera or Apple's iWatch or iPods instead.

According to a recent report from KDB Daewoo Securities Research, Apple will releases its newest smartphones in the second or third quarter of this year. Other rumors suggest that Apple will debut the iPhone 6 at the Worldwide Developer's Conference in June. Based on the company's release patterns, Apple will likely release new phones to the public in the fall, one year after the release of its newest smartphones, the iPhone 5s and iPhone 5c.