Natural stone tiles can be stained by spilled liquids; they must be sealed and periodically resealed with a sealant in contrast to ceramic tiles which only need their grout lines sealed. However, because of the complex, non repeating patterns in natural stone, small amounts of dirt on many natural stone floor tiles do not show. Ceramic tiles and some stone tiles such as polished granite and marble are inherently very slippery when wet.
Ceramic tile for use in wetrooms can be made more slip resistant either by using very small tiles so that the grout lines acts as grooves or by imprinting a contour pattern onto the face of the tile. They typically have a glazed upper surface and when that become scratched or pitted the floor looks worn, whereas the same amount of wear on natural stone tiles won't show or will be less noticeable.
