Drywall cement! Yes, it's true. This is made with drywall cement layered over a wooden center for strength. This is a fairly easy project to do, it just takes a little patience. You must put on a layer of drywall mud, let it dry and repeat. The final layer is the Celtic knot stencil that is slightly embossed on the surface of the tile. I hope to do a step-by-step guide for this soon.