The iPhone 6 on release date will be sporting new and improved mobile device features that cost Apple a total of $938 million to develop.

The near-billion dollar bill was mainly headlined by Apple's decision to invest heavily on a U.S.-based factory that produces sapphire glass coatings and the recent takeover of Israeli firm PrimeSense, which was responsible for the 3D sensor technology used by Microsoft in the Kinect controller for the Xbox 360.

To ensure that it has a steady source of sapphire glass materials for its upcoming iOS devices, Apple spent a whopping $578 million. The splurge, according to UK-based tech site Mirror News, will lead to the iPhone 6 boasting of sapphire-protected body make.

Sapphire is already in used as protective coating for the Touch ID fingerprint scanner and rear camera lend deployed with the iPhone 5S.

Also, it is likely that Touch ID on the iPhone 6 will become more of a mini trackpad, according to The Huffington Post, giving sapphire coating a more crucial role in the next iPhone ecosystem.

Chiefly, sapphire is meant to bump off Corning Gorilla Glass as the iOS device screen guard though for the iPhone 6, the coating will cover the whole device, leaving the handset virtually scratch proof.

Now for the $360 million PrimeSense acquisition, per a BGR report, numerous possibilities have been emerging on how exactly the Kinect-like technology will be played out in the iPhone 6. One likely implementation is the use of the technology to make the handset a powerful gaming tool.

Another is for mapping and navigational purposes, signalling that Apple is looking to match the supremacy currently enjoyed by Google Maps with the help of advanced 3D sensors.

However, 3D sensing capabilities would be more useful in making Siri a smarter personal digital assistant. "PrimeSense's technology can help Siri identify the present physical context of the user (and) will make the service more intelligent-seeming and perceptive," Forbes said in a report.

Regardless of how Apple plans to make use of its recent heavy investments to keep its iOS devices ahead of the competition, it is clear that the tech titan is not skimping to deliver the best possible specs and features for the smartphone that analysts said will replace the iPhone 5S.

Apart from these rumoured killer features, the next iPhone is believed to flash a 64-bit A8 processor, 4GB of RAM, a Liquidmetal casing that makes the device almost indestructible and a 5-inch wraparound display screen.

The iPhone 6 release date is pegged by analysts to take place on the second half of 2014, with some predicting that debut time for the first Apple phablet could happen as early as June of the same year.