Is Apple's Watch in jeopardy? Crisis at firm making sapphire screen for wearable deepens

• GT Advanced Technologies has been working with Apple on sapphire glass plant      
• Filed for bankruptcy last week     
• Apple says it will 'continue to evaluate the firm' but admits it is looking at other options to source screen  

The company that was due to make the scratchproof sapphire glass screen for the Apple Watch it still in crisis and may be forced to shut down, it has been revealed. 

GT Advanced Technologies, a former stock market darling and supplier to Apple, filed for bankruptcy on Oct 6 in a stunning turn of events for a company whose fortunes looked bright only a few months ago.

Apple said on Thursday that GT's 'ambitious' vision of sapphire manufacturing was ultimately not quite ready for primetime.

Few details have emerged since the bankruptcy filing, which wiped out most of GT's market value and triggered speculation over what may have soured its relationship with Apple.

But on Thursday, Apple, which had backed the development with GT of a sapphire-manufacturing plant in Arizona, said it will keep an eye on GT's advances, holding open the possibility of doing business with it in future.

'Apple put a lot of effort into an ambitious new sapphire manufacturing process with GTAT which is not ready for production. 

'We're going to continue evaluating GTAT's progress on larger sapphire boule development, as well as consider other options for the facility,' spokeswoman Kristin Huguet said, referring to raw cylinders of the material.

At the heart of GT's bankruptcy filing was a deal struck with Apple in November 2013. 

GT Advanced was to have used the Arizona plant to make scratch-resistant sapphire exclusively for Apple. 

That sapphire was to have eventually found its way into future mobile devices, such as iPhones - where it's already in use in their fingerprint sensors - or the upcoming Apple Watch.