Saltillo tiles are very popular in Tucson homes, and they have a warm, informal, Mexican style that goes well with Southwestern architecture and decor. These red clay tiles are handmade in Saltillo, Mexico from that area's reddish clay. Saltillo tiles are laid outside to dry before firing, and you can occasionally find animal prints in them like this dog or coyote print.
Imperfections such as these are just considered part of the charmingly rustic character of Mexican Saltillo tiles.