According to the report by UBS Research analysts, GT Advanced Technology has begun shipping sapphire material to China.
Production reportedly began about a month ago and a small number of prototypes will be manufactured, instead of a real mass production.
GT Advanced reportedly shipped 2,200kg of sapphire, an amount produced by a number of 100 active furnaces at the plant.
It is said that the company will install another 400 to 500 furnaces in the first quarter of 2014 and is ready to add another 900-1000 in the second quarter to ramp up production for devices like the iPhone 6 and iWatch.
In November 2013 Apple signed a $578 million deal with GT Advanced Technologies.
Sapphire crystal is already used in the iPhone 5S in the home button and the camera on the back.