Foxconn has apparently started producing iPhones with sapphire displays, Taiwanese publication Apple Daily has learned, with the Chinese manufacturer expected to make 100 iPhone units with such display cover glass. This isn’t the first time Apple is associated with sapphire usage in mobile devices. The current iPhones have cameras with sapphire protection, and the iPhone 5s’ fingerprint scanner is also guarded by sapphire glass. Furthermore, Apple already has at least one patent on sapphire glass use in smartphones, and has confirmed during an interview last week that its Arizona plant will produce sapphire glass, without revealing what devices will use it in the future.

However, not many details are known about this iPhone trial run conducted by Foxconn, as the publication has not revealed what kind of iPhone models are being produced, and it’s unlikely Apple will confirm anything related to its future iPhone models.

The same publication says that Apple sapphire suppliers Synopsys and Bern Optics have invested in cutting machines and other sapphire-related machinery, suggesting that Apple may be getting ready to increase its sapphire usage in the future. MacRumors reports that Apple has also been working with Swiss company Meyer Burger Technologies to obtain new sapphire cutting machines.