Just shattered the Screen of my iPhone 6S Plus

[Newtons Apple]

Sort of. As hardness of a material increases, so does it brittleness. That is correct. However, the force required to break it is still higher as the hardness increases.

Take a diamond for example which is the hardest natural material, if you put it in a very sturdy and very hard vice, and swing a very hard hammer at it, it is possible to break into a hundred little pieces due to it's brittleness. However, breaking it like that will still require a significant force.

Also, there is more to scratch-resistance than just material hardness. There are various polymer technologies that address scratch-resistance. For example, there are coatings made from self-healing polymers that are quite good at being bumped by hard things and not leaving a visible mark.

Great maybe Apple can use one of the "self healing Polymers one day. Until then physics will rule on the iPhone, sort of.