What Is Sapphire, The Super-Tough Display Material That Might Come To The iPhone?

Your questions: Answered!

What Is Sapphire, The Super-Tough Display Material That Might Come To The iPhone?
[Sapphire: Imfoto via Shutterstock]

On Thursday, the Wall Street Journal reported that Apple is sinking $700 million into a new material for the iPhone’s touch screen. It’s called sapphire, a super-tough substance that, if it ends up being implemented into the iPhone 6, could cut down on the multitude of sad and shattered iPhone displays floating around out there. Here’s what you should know about it.


What is it?
It’s a hard, crystalline material with a number of properties similar to Gorilla Glass, the stuff currently used to make iPhone screens. Sapphire is transparent, incredibly flexible, strong, and doesn’t scratch as easily as glass, making it more resistant to cracks should you drop it. And since it’s tougher, it could lead to thinner iPhone displays–although you probably wouldn’t notice the difference.

The sapphire we’re talking about here isn’t the same stuff found in the Earth. It’s a synthetic lab-created material that approximates a real sapphire’s structural properties. In fact, your current iPhone already has a tiny bit of this new material in it.

Wait, Apple already uses it?
Yep! The iPhone’s camera lens is covered in sapphire to keep your pictures from looking scuffed up. On the iPhone 5S, sapphire is used to cover the fingerprint reader.

Where else is sapphire used?
Airplane windows. Pricey watch faces. Armored vehicles. Stuff like that.

How hard is it?
Sapphire is one of the toughest minerals on Earth–harder than steel, though more fragile than diamond. “Chemically strengthened glass can be excellent, but sapphire is better in terms of hardness, strength, and toughness,” Matthew Hall, director of the Center for Advanced Ceramic Technology at the Kazuo Inamori School of Engineering at Alfred University, told TechCrunch last September. “The fracture toughness of sapphire should be around 4 times greater than Gorilla Glass.” On Moh’s scale of hardness–the metric used to grade the hardness of minerals–sapphire is a 9 out of 10.

The Wall Street Journal published a nifty chart illustrating how tough sapphire is.


Why don’t more phone-makers use it?
Sapphire has a few downsides. For one, it’s more reflective than glass, so glare could be a problem. And Corning, the makers of Gorilla Glass, the material that sapphire could be replacing, claims that they have been working with lab-grown sapphire since the 1970s; they say it’s not as tough as it’s made out to be, per in-house tests. (Make of Corning’s findings what you will, obviously.)

More importantly, sapphire is expensive, which is why it’s currently used sparingly. (Each sapphire screen could cost Apple $16 versus the $3 it currently spends on Gorilla Glass.) Apple nevertheless would like to change that, which is why it’s sinking $700 million into ramping up the world’s sapphire production…

Yeah, about that. Where are those hundreds of millions going?
Last year, Apple bought an enormous new factory in Arizona. It’s huge, about the size of two-dozen football fields. Now Apple is leasing the property to GT Advanced Technologies, a company that specializes in developing crystalline materials, which will house its sapphire-producing furnaces there. Analysts predict that, if all goes according to plan, the new plant could produce twice as much sapphire as all the world’s sapphire makers combined.

Okay, last question: Will it be on the next iPhone?
Here’s a definitive “maybe.” Market analysts aren’t optimistic, citing production problems. Then again, this is Apple we’re talking about.


About the author

Chris is a staff writer at Fast Company, where he covers business and tech. He has also written for The Week, TIME, Men's Journal, The Atlantic, and more