Remember in middle school when you had to tote around a sack of flour or a little egg with a Sharpie smiley face on it? Back then we thought we were prepping ourselves for motherhood in an admittedly weird way, but now we know — we were just gearing up for the responsibility of having to carry around our most important info on a very breakable glass brick at all times. The practical iPhone users among us (as well as those of us who cracked an egg-baby way back when… and then our smartphone screens just last weekend) have had “more durable screen” on the top of our iPhone 6 wish list, and now a new video shows just how durable that piece of protective glass could be.

Maybe you saw the one where tech reviewer and vlogger Marques Brownlee put a supposed iPhone 6 screen under an intense durability test.

He stepped on it, tried to bend it, scratched his keys on it and stabbed it with a fairly scary knife — and that bad boy held up well under these everyday pressures.

But as Marques explains in his latest video, knives and keys aren’t actually that hard when you compare them to sapphire glass so yeah, they shouldn’t scratch or dent it. To see what the iPhone 6’s rumored new screen can truly withstand, Marques busts out the Mohs Scale of Hardness and puts it all into perspective.

Since sapphire is the second hardest naturally occurring material on Earth, we need a better test to put it through than just the delightfully dramatic stab test. In this seven minute video, Marques uses two different types of sandpaper on iPhone 5’s Gorilla Glass screen and its home button (which is made of pure sapphire) and then on the iPhone 6.

The iPhone 6 display proves to be harder than Gorilla Glass, which means it will put up with even more wear, tear and tumbling around in your purse or pants. Since the iPhone 5’s home button stood up better to the sandpaper than the iPhone 6 screen, it looks like the 6 is made of a sapphire blend. A pure sapphire screen would bring up the price on that upgrade and not be flexible enough to give your phone the slight bend that it needs — so this is good news.

Watch to the end of the video to really see whether or not the iPhone 6 screen is breakable when it’s put to the ultimate test, the crossbow test. #ow

Is having a more durable screen on the top of your iPhone 6 wishlist? What does your current smartphone screen look like? Share below!