Desay Magical Mirror X5 smartphone
Desay Magical Mirror X5 has an 'unbreakable' sapphire screen Desay

A Chinese supplier to Apple has released a smartphone with a sapphire crystal screen, fuelling speculation that the iPhone maker could finally introduce the near-unbreakable material to its next handset.

Shenzhen-based Desay has started taking pre-orders for its new 5in smartphone, called the Magical Mirror X5, through China Mobile, the world's largest network by subscribers. It is priced at just 999 yuan ($160, £105), one-fifth the price of the current glass-fronted iPhone 6.

Bizarrely, a promotional video for the Desay phone shows off the screen's strength by dropping it into a chestnut mixing machine.

It had previously been understood that producing sapphire-crystal panels instead of glass on the scale required by Apple would be too expensive; until recently, the material was only found on premium watches and luxury smartphones like those produced by Vertu, which sell for upwards of £5,000.

Desay's battery-producing business - Shenzhen Desay battery Technology - was included in Apple's 2014 supplier list, prompting speculation that the company could extend its relationship with Apple to include the new phone's sapphire screen.

However, analysts believe the Magical Mirror X5 will only be available in small quantities as the low retail price is "unlikely to cover the production cost" given the slim design, high specification and use of sapphire, the Wall Street Journal reported.

Forrester analyst Gene Cao poured cold water on the phone, saying: "It's a smart marketing campaign to promote its nascent brand. But I doubt if all of its Magical Mirror X5 phones would actually feature expensive sapphire screens as customers cannot tell the difference between a hardened glass and a sapphire."

Apple has shown interest in sapphire for some time, having partnered with GT Advanced Technologies and in 2013 announcing a $1 billion plan to build a factory in Arizona to produce the material; but Apple hasn't used it in any products to date, and GT filed for bankruptcy in October after failing to mass produce the material.

Apple has said some models of its upcoming Watch will feature a sapphire crystal display, but at just 42mm wide, this component is much smaller than what would be required to cover any future iPhone.