No, the iPhone 6 or iPhone 6 Plus do not have sapphire displays. Both displays are "ion strengthened," which is the same process used by Corning to produce its Gorilla Glass used on other smartphones.
Apple has not announced official specs regarding how much RAM is built into the iPhone 6 or iPhone 6 Plus.
Leaked benchmarks have indicated the iPhone 6 sports 1 GB of RAM. This is the same amount of RAM found on the iPhone 5s.
More RAM does not always improve mobile device performance, as the additional chips can expend more battery power.
Yes, both the iPhone 6 and iPhone 6 Plus have NFC (Near Field Communication) technology. Both devices use NFC for Apple's new mobile wallet service Apple Pay. iPhone 6 users can use Apple Pay by tapping their device on payment terminals located at participating merchants to electronically pay for in-store transactions.
The new iPhone 6 and even the larger iPhone 6 Plus are both heavier than their predecesor, the iPhone 5S.
The iPhone 6 weighs in at 4.55 ounces (129 grams).
The iPhone 6 Plus weighs in at 6.07 ounces (172 grams).
For comparison, the iPhone 5S weighs 3.95 ounces (112 grams).
Apple calls the new iPhone 6 and iPhone 6 Plus "dramatically thinner," and while the word is that the new model does feel significantly thinner in the hand, the reality is that it is about 10% thinner than the previous model.
The new iPhone 6 is 6.9 mm thick.
The new iPhone 6 Plus is 7.1 mm thick.
As a comparison, the iPhone 5S is 7.6 mm thick.