http://www.deserttileandgrout.com/mexicantile.asp
Since much of the ambience of Arizona is steeped in Mexican culture, including building and decorating styles, Saltillo Tiles and Mexican Tiles are extremely popular.

Saltillo tile is a type of terra cotta tile that originated in Saltillo, Mexico. These tiles are made from natural clay and mostly produced in Mexico. They have a distinctive rustic appearance and sometimes contain animal tracks made during the drying process, which are said to be good luck. True Mexican tile is made by hand and fired at low temperatures. These tiles vary in color depending on where the tile was placed among the other tiles when they were fired.