Everyone was all hyped up about sapphire crystal displays a few years ago, then manufacturers realized what a complete pain in the butt it was to manufacture synthetic sapphire at an industrial scale. There have been a few phones and watches with this super hard material covering the screen, but Zagg offers a "Sapphire Defense" screen protector, too. That makes it sound like a sapphire glass screen protector, and the high price backs that assumption up. However, JerryRigEverything just posted a video revealing it to be nothing more than treated plastic.
If you're not familiar with JerryRigEverything's torture test videos, he always uses Moh's Hardness Picks to test the scratch resistance of the screen. Hardened glass displays usually scratch at level five or six. Sapphire, which is one of the hardest natural materials, scratches at a level eight or nine. The video tests the hardness of three products that advertise sapphire: a Tissot watch, the special edition HTC U Ultra, and Zagg's $50 Sapphire Defense hybrid glass screen protector.
The U Ultra and Tissot watch scratch at level eight and nine, as expected. That's better than glass screens, so you're unlikely to scratch one of these devices unless you've got diamonds in your pocket on a regular basis. Zagg's $50 screen protector scratches at a level three. That's what you'd expect from plastic, and indeed, it appears to be made of plastic. When exposed to fire, it melts and burns. Sapphire does not do that, nor does glass (at these temperatures).
So what's going on here? Zagg's packaging says the screen protector is "infused with sapphire." JerryRigEverything notes there are traces of aluminum oxide (sapphire) in the plastic. So, Zagg wants you to assume this is sapphire glass, which it is not. It's not even glass. I feel like this goes a little beyond marketing spin and into straight up deception. Shame on you, Zagg.