For a little while, sapphire screens (or at least rumors of them) were all the rage. Sapphire is far harder than even the special Gorilla Glass that coats modern smartphones, so an all-sapphire device should be nearly unscratchable.

Since sapphire screens didn’t go mainstream, accessory maker Zagg decided to do the next-best thing: make a “sapphire” screen protector that claims all the benefits of sapphire for whatever phone you apply it to.

Unfortunately, it all looks like a bunch of marketing crap.

YouTuber JerryRigsEverything decided to test the $50 Zagg “Sapphire Defender” screen protector against two pieces of actual sapphire, from an expensive watch and an HTC Ultra U. Jerry is famous for his scratch tests, which he does with a series of picks of different hardness. They’re graded on the Moh hardness scale, a universal standard for the toughness of a material. Normal glass screens scratch at around a 5-6 (1 is the weakest, 10 the strongest), and the sapphire screens went all the way up to 9.

The “sapphire” screen protector, on the other hand, started to scratch around a 3. That’s the same as most other plastic screen protectors, so Zagg’s “sapphire” technology is either ineffective or a total lie.

Chris Mills has loved tinkering with technology ever since he worked out how to defeat the parental controls on his parents' internet. He's blogged his way through Apple events and SpaceX launches ever since, and still keeps a bizarre fondness for the Palm Pre.