You can spout all the numbers you want (and comparing ion x to a version of gorilla glass is mute - you don't know the numbers, or whether ion x is stronger/weaker than this).
It is pretty well known that sapphire will crack easier than even gorilla glass under most circumstances. Search around - you will see many articles/videos testing/reporting on this. It is a balance between scratch resistance and shatter resistance. For most people on a watch, scratch resistance is probably going to be preferable.
If you are a PhD/Postdoc/whatever, you should know that using the figures from a completely different product to prove an argument is fruitless.
I'm not seeking to "prove" anything. I have a hypothesis that I am supporting with the best available data and reasoning at my disposal.
Other than Apple buzz marketing, neither you nor I have any idea about the specific numerical property values of Ion-X. So, in the absense of that, I'm using the best available data of similar products, with the stated caveat that they are not identical.
If you're argument is I can't do that, well I disagree. If I want to compare the properties of two things — say, the Young's modulus of gelatin and saltine crackers, I can make some broad characterization that serve as a reasonable starting point for a hypothesis. Yes, there are different brands of gelatin and crackers out there and they'll have different moduli, but there will be a range of property values that can still be reasonably established. There's a whole field of materials research dealing with evaluating and classifying properties. Properties within a family have ranges but tend to group together. They make very pretty bubble plots.
Now, I'm open to the idea that this new glass apple is using (which may very well be an existing familiar product that they are branding with this new moniker) could be a very good glass in terms of toughness. Maybe it's even the best, toughest glass on the market. But even still, the hurdle in property magnitude that would have to be crossed to reach the toughness of sapphire is pretty big.
The testing you mention of sapphire's brittleness, at least the ones I've seen, reference studies done by Corning (the manufacturer of Gorilla Glass). Corning itself focuses mostly on the advantages of its lower weight and lower cost. Their strength of materials results...are a little less clear, and are definitely stated with a little less bravado. I'm not saying the tests are invalid, but I'm also going to point out that Corning is not an independent, impartial party in this discussion. Their results have been filtered through various levels of corporate hierarchy before they were churned out as a marketing document. Again, they could be spot on, but this is not a peer-reviewed study. There's generally a lot of hand-waving and misdirection (coincidentally, Apple does this as well as any other company out there). It's basic entrepreneural strategy — you amplify and magnify the strengths, and you soft pedal and obscure the weaknesses.
Corning exec is quoted: "What would people say if someone invented a cover that was about half the weight, used 99 percent less energy to make, provided brighter displays, and cost less than a tenth of sapphire? I think they’d say that sapphire was in real trouble."
Okay, so those are the real advantages of glass. The ones the leading glass manufacturer used as the "elevator speech" talking points.
Now what do they have to say about the durability of the material? From the same Corning press release: " In one of our commonly accepted strength tests, sapphire breaks more easily than Gorilla Glass after the same simulated use. Additionally, sapphire’s cost and environmental hit are huge issues."
There's a big change in surety there. In "one test" of simulated usage, with conditions defined by the biggest glass producer out there, they were able to get the sapphire to break first. Huh. That's interesting. Also, a shift in focus back to the other established advantages of glass, which they are confident about and don't want you to forget about.
I can tell you that when you're doing a testing protocol, you can almost always find at least one run, or one specific condition, where you can get the result that's "desirable." Industries use this kind of behavior all the time. It is much closer aligned to what the marketing department needs.
So, with all that said, who's right? I don't know. My point wasn't to prove right or wrong, it was to provide the best evidence I have for my hypothesis. Take it or leave it. I guess maybe somewhere down the line, there will be some data about incidence rates of Apple Watch faces shattering, and the debate can be revisited!
And hey, if it means anything, I will probably buy the Sport edition! I'm betting it wouldn't fare a drop as well, but I'm willing to bet with my dollars that it will hold up just fine if it's cared for.
