Apple’s new manufacturing facility in Mesa, Ariz. isn’t even completed yet. Nonetheless, plans are already underway to expand the facility where sapphire glass is being made, according to AppleInsider.

Collectively dubbed “Project Cascade,” the current structure sits on an 83-acre plot of land designated by the City of Mesa as a foreign trade zone. Apple and GT Advanced Technologies are already using the facility to produce sapphire glass for next-generation iOS devices.

AppleInsider says the expansion could help “accommodate higher yields for an as-yet-unknown component.”

To date, sapphire glass has only made an appearance on the iPhone 5s handset’s home button. The “unscratchable” material is also used to protect the built-in cameras which appear on the iPhone, iPad, and iPod touch.

Sapphire glass is likely to be the main component in next-generation iOS devices, including the “iPhone 6″ and “iPad Air 2.”

Earlier this week, the first images of Apple’s Arizona sapphire plant surfaced online.

See also: Apple Not Expected To Join ‘Megapixel Horserace’ With 2014 iPhones, and The Latest iPhone 6 Concept Is Big, Beautiful, But Square?