New scratch test shows that iPhone 6 panel may not be pure sapphire after all


Could it be that the much-anticipated sapphire displays for the upcoming iPhone 6 isn’t actually sapphire at all? Sort of, according to a new video posted by YouTuber Marques Brownlee.

Brownlee made waves a few weeks back when he apparently managed to get hold of one of the super-tough 4.7-inch displays reported to feature in Apple’s next generation handset, and ran it through the most brutal assault course this side of Full Metal Jacket. The display was subjected to a scratch and shatter test involving keys, a knife, and even Brownlee himself trying to bend it with his foot.

Provided the display (supplied by renowned Apple leaker Sonny Dickson) is genuine, this test suggests that the iPhone 6 screen will be considerably stronger than the displays used in its predecessors.

But it may still not be pure sapphire. Here’s why.

In a new video shown above, Brownlee tests the panel once again, this time using the Mohs scale of mineral hardness. The Mohs scale, for those who don’t know, runs from 1 to 10 — with 10 being hardest. A mineral can scratch anything below it on the list, but nothing above it. Since Brownlee’s steel knife rated a 5.5, he explains that it would have been unable to scratch either Gorilla Glass 3 (6.8 on the scale) or sapphire crystal (a 9).

To put the display through a more accurate set of tests, Brownlee tests it again using both garnet sandpaper (a 7 on the Mohs scale) and emery sandpaper (an 8), with both successfully scratching the panel, but not scratching the pure sapphire used for Apple’s Touch ID on the iPhone 5s.

This suggests that the iPhone 6 does not feature pure sapphire: something which may be for the best, since a pure sapphire display could prove prohibitively costly and without the necessary flexibility for a smartphone screen.

In fact, Apple has previously filed a patent application for a hybrid sapphire laminate, which could well turn out to be the material being used for the iPhone 6 screens.


Apple’s March 2013 patent application shows how glass and sapphire could be bonded together to form a sapphire laminate.

Earlier this year, Apple opened its own sapphire manufacturing plant in Arizona, to manufacture what was described in paperwork as  “a critical new sub-component” for a future Apple product.

More recently it has been suggested that sapphire displays may feature only in the more expensive 64GB iPhone 6 — a rumor I personally hope is untrue, since it could needlessly complicate and fragment the iPhone 6 product line, particularly when considered alongside a previous rumor that Apple’s reported image stabilization feature will be available only on the 5.5-inch “phablet” iPhone.

Sapphire or sapphire laminate, the new iPhone 6 is expected to launch this September, featuring a new rounded design, improved processor and camera, and a host of other features.

About the author

Luke DormehlLuke Dormehl is a UK-based journalist and author, with a background working in documentary film for Channel 4 and the BBC. He is the author of The Formula: How Algorithms Solve All Our Problems, And Create More and The Apple Revolution, both published by Penguin/Random House. His tech writing has also appeared in Wired, Fast Company, Techmeme, and other publications. He'd like you a lot if you followed him on Twitter.

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