I haven’t done any deep impressions, so don’t know about the cracking. They do absorb water, much like the coasters at a bar. But, if you spray them with an automotive enamel (both sides) then they last much longer. I found a triple-thick auto glaze that is like a resin surface, so there’s always that. The auto finishes are better and more stable than artist acrylic gel, which sometimes is too sticky (and not sprayable).