Nope, diamonds wear and fracture. As said, do a quick Google search.

Or, lap an Ark with a new diamond plate…

Chipped Diamonds (the agonizing reality) 3 Examples

"Everybody knows that diamond is the hardest mineral substance on earth. So you might be wondering why we have a page about chipped diamonds. Well, the key word to focus upon here is mineral.

Diamond is not the hardest thing on earth, it is simply the hardest mineral. The reality is that you can scratch the surface of a diamond with the pop-top from a can of soda.

Right about now, your mind is probably swimming with the possibilities, so we might as well finish it off. You can actually crack a diamond trying to scratch glass! Understand that I’m not saying the old myth that diamonds scratch glass isn’t true, because it is. I’m simply advising you not to rely upon that method to determine whether a diamond is real. Holding the diamond at the wrong angle, or applying too much pressure can cleave the diamond in two. Imagine the look on little Johnny’s face when that little science experiment fails!"