Coasters made of polished agate stone. Agate is a type of chalcedony and the coasters are dyed in the colors blue/green/pink/purple. We also offer coasters in naturel colors. Because Agate is a natural material, every coaster is unique and not one of them is exactly the same. The diameter is between 8 and 11 centimeter. One set of coasters consists of four coasters. The bottom has silicone caps to protect tables. When you order you will receive different colors.