Corelle Heirloom Bloom Absorbent Stone Coaster, 4-Pack Four Corelle licensed absorbent coasters Coasters are made our of ceramic bisque, a naturally absorbent material and have a cork back to prevent scratches to fine surfaces The heirloom Bloom pattern from Corelle is featured on these absorbent coasters Simply soak coaster in hot water with a liquid detergent rinse and let air dry We will fully replace your Corelle coasters if defective