Review on Thirstystone 4 Piece Southwest Cactus Coaster by Richard Summerall

I live in an area of Sedona where Thirstystones are sold in every gift shop. I bought four Thirstystones individually (as opposed to a set) and am very happy with them. However, the set does not absorb condensation that drips from drinking glasses. I think it's because of the material used to paint the cactus. I am returning this set and replacing it with a set that has no design other than the natural design. formed from sandstone.