Coaster sets are made using 4in x 4in ceramic tiles and resin. All are different and unique. Sets with less layers and involvement are lower priced and sets with more layers are higher priced. All are cork bottomed and tied together with various complimentary colored ribbons. Perfect for gifting! These are functional pieces of art meant for light, casual use and display. (IE: Wine glasses, plastic, etc. )Not dishwasher safe and not recommended for heavy, scratchy pottery and porous, non glazed cup bottoms that could scratch the surface. Not meant for extremely hot liquids either. Please treat them with care.