- Set of 4 - 13cm diameter (5.12 inch) Hand Cast Rocks GREAT for mandala dot painting, coasters or crafts -Smooth surface for painting -Great for indoors OR outdoors! Because each set of stones is hand cast, there may be small imperfections or microbubbles on the bottom unseen surface (although I do my best to avoid these). Stones sit flat. The top and sides will be smooth for painting. US PURCHASES ONLY