I listened to someone talk about them yesterday. I have forgotten the exact example they used, but evidently they are quite brittle. I'm afraid I can't quantify that for you, but they are not hardy. They can be damaged by what you and I might consider light impact. Would that totally incapacitate them? I don't think so. Care is certainly called for in handling them. I got the impression that an impact could certainly damage them.
Sorry I couldn't pin that down better.
Other tiles, ceramic floor tiles in fact are quite brittle..
If you step on or drop one you will certainly break it.
With materials like this their strength comes from the backing material, it distributes the load evnely and keeps the tile from hinging..
I wonder if the backing was damaged, if a whole "sheet" of tiles couldn't come loose and peel off.
If tiles are the issue, I bet backing is the cause.