After a day of dirty, sweaty rock and mineral collecting, I like to come home to an ice cold beer or glass of water. However, I can’t stand having those little ghost rings on my table from the condensation on the bottle. So what do I do? Use a coaster! These beautiful agates are genuine specimens and are guaranteed to wow your rockhound friends. At $60 for a set of four, these colorful conversation pieces are sure to brighten up any desk or dinner table.