Apple and the state of Arizona have announced a second Apple factory in the US - in Mesa, Arizona - as Apple works to bring some manufacturing back to its home country. The factory will be in partnership with GT Advanced, which will "own and operate furnaces and related equipment" at the Apple facility.

"We are proud to expand our domestic manufacturing initiative with a new facility in Arizona, creating more than 2,000 jobs in engineering, manufacturing and construction," Apple announced in a statement.

 "This new plant will make components for Apple products and it will run on 100 per cent renewable energy from day one, as a result of the work we are doing with SRP to create green energy sources to power the facility."

The purpose of the factory hasn't been explained by Apple, though GT Advanced says it has entered "into a multi-year supply agreement with Apple  to provide sapphire material". Sapphire is used abundantly in Apple products, including the Touch ID fingerprint sensor and camera lens in the iPhone 5S. This gels nicely with the word about "components".

The GT press release adds: "Apple will provide GT with a prepayment of approximately $578 million. GT will reimburse Apple for the prepayment over five years, starting in 2015." 

The Arizona factory follows an Apple-backed factory from Flextronics in Fort Worth, Texas, that will be the hub of most of the Mac Pro's manufacturing. Apple has touted the "made in the USA" fact heavily in several marketing campaigns. On the east coast of the US, Apple has also opened an AppleCare centre in Pennsylvania to speed up some repairs. 

"Apple is indisputably one of the world’s most innovative companies and I’m thrilled to welcome them to Arizona," Arizona Governor Janice K. Brewer said in a statement. "Apple will have an incredibly positive economic impact for Arizona and its decision to locate here speaks volumes about the friendly, pro-business climate we have been creating these past four years."

From an environmental standpoint, Apple is said to have advanced green energy in Arizona. Apple's "investment in renewable energy will also be greening our power grid, and creating significant new solar and geothermal power sources for the state", Brewer said.