Roca Moda Agate Coaster set. Each coaster is approx. 3.5 inch - 4 inch in diameter, one of a kind, crafted from natural agate with a polished finish and silver plated edges. Each coaster has 4 clear bumpers on the bottom for surface protection. Comes in a set of 4. The naturally occurring patterned rings add elegance and beauty to your coffee table, night stand, desk and end table.