Handcrafted tumbled marble coasters by Studio Vertu. Each set/4 of coasters is handcrafted by our trained artisans in Kentucky. Because we use natural stone, variations are to be expected, and enhance the unique beauty of each tile! To clean, use a damp cloth and wipe clean. Do not use any harsh chemicals or abrasives. Dimensions: 4x4 tumbled Botticino marble. Corked backed