Describing something normal so that it sounds weird - take two

I have a collection of things one uses to stop your possessions from getting wet. Sometimes they're made of rock or metal or ceramic or some kind of wood product. They can be square or round. They're most often decorative and stylish and it's really annoying when visitors to your house choose not to use them. My grand-daughter uses ours as building blocks.

I'm speaking of course about coasters.