<https://samsengravingandgifts.com/products/round-slate-coaster#product>
<http://schema.org/description>
"Purchase single coasters, or a a 4-Piece Set\nThese Slate Stone Decor pieces make great corporate or personal gifts! Customize them with your choice of engraving. Each Piece varies slightly in exact shape and color, these are real slate so no two are identical. Includes foam pads to protect your surfaces. 4\" round\nMade of actual stone with chipped edges. Sizes may vary.There are 4 foam dots on the bottom.Coated with a scratch resistant Food Safe Coating.\n\n\n\nLength\n4\"\n\n\nWidth\n4\"\n\n\nThickness\n1/4\n\n\nOverall Size\n4\" x 4\" x 1/4\" thick\n\n\n\n"
<https://samsengravingandgifts.com/products/round-slate-coaster>