Over the past couple of weeks, YouTubers have been conducting all kinds of "tests" on the new iPhone 7 and iPhone 7 Plus, looking for flaws, confirming Apple's design claims, and exploring new features. One test on the sapphire cover of the rear-facing camera, calls into question whether lens cover is indeed made of sapphire after it's shown being scratched with picks designed to emulate the Mohs hardness scale.
On the Mohs scale of hardness, sapphire rates a 9, coming in just under diamond at a 10 on the top of the scale. Its hardness makes it resistant to scratching, and so it's used by high-end watch makers and by Apple to cover the Home button and the rear camera of the iPhone 7.
In the video, scratches are made on the iPhone 7 camera and a sapphire-equipped Tissot watch using specialized Mohs tools. With a pick the reviewer claims is "Mohs 6," he is able to make scratches on the camera lens, theorizing that it is made from sapphire-laminated glass or impure sapphire because sapphire should resist scratches at Mohs 6.
This test, and others like it, have caused people to claim that Apple is lying about using pure sapphire crystal over the camera lens, prompting the company to release an official statement
subtly calling into question the testing methods used in the video. The reviewer does use tools to determine the composition of the sapphire and finds carbon, but it is not clear that the test was done without contamination.
Apple confirms the iPhone 7 camera lens is sapphire, and under proper testing conditions, achieves the hardness and purity results expected from sapphire.
Last month, Apple's Phil Schiller also confirmed on Twitter that the rear lens cover on the iPhone 7 and the iPhone 7 Plus are constructed from sapphire.
According to iMore's Rene Ritchie, there's a simple explanation for the discrepancy between Apple's claims and what's going on in the video. The tools used in the video aren't scratching the lens -- they're causing fracturing, as can even be seen when the sapphire is placed under the microscope, due to heavy pressure.
Fracturing -- as opposed to scratching -- is what happens when you have something so incredibly thin -- unlike the much thicker watch used for comparison -- and you apply pressure with no level of control.
You'd have to precisely apply the same level of force, likely to the same thickness of material, to properly do that test.
Apple has used sapphire crystal for iPhone components for multiple years and maintains that sapphire crystal continues to be present in the iPhone 7 and the iPhone 7 Plus, a conclusion that was also ultimately reached in the video.