We have already started reading / hearing a lot about the iPhones 6s / 6s Plus. In a nutshell they will be very, but very visually similar to the current iPhones 6/6 Plus, but with some enhancements including the addition of Force Touch technology, rear and front camera enhancements, new color (pink or rose gold), a sturdier body (made from the same material as the Apple Watch Sport alumnio 7000 series), among other things.
For, except for a hole here and another there, the images shared by the site Future Supplier (as noted by NWE) "Prove" this, if they really are true that the future iPhone even has a virtually identical housing to the current device.
The truth is that it doesn't have to be a genius to know that, just take the Apple release history (iPhone 3GS, iPhone 4s and iPhone 5s) and see that they are visually quite similar to their direct predecessors. However, even though the casing's gold is exactly the same as the current one, the website's source said the material used was different, corroborating the idea that we will see tougher aluminum on the iPhone 6s (goodbye, #bendgate).
There is nothing to indicate that the iPhone 6s come with a sapphire crystal screen, but if it happened to come, it would undoubtedly be one of the toughest smartphones on the market.