When they said they are made of "absorbent stone", they weren't kidding.

The MIWARE Coasters are nice and heavy (in a good way), which makes them stay in place and they don't slide around at all on my glass tabletops. When they said they are made of "absorbent stone", they weren't kidding. Somehow sweat from the beverages doesn't seem to pool on these coasters, unlike other ones I've used in the past. They worked better than I expected, and they look very elegant on my coffee table and end tables. I am pleased with my purchase and I would definitely recommend these to others.