Most types of tiles made from a form of clay or a clay mixture and kiln-fired are considered to be a part of the larger classification of tile called ceramic. These tiles can be split into two groups, porcelain tiles and non-porcelain tiles, and the non-porcelain tiles are commonly referred to as ceramic tiles.
Non-porcelain ceramic tiles are generally made from a red or white clay that's fired in a kiln. They're easier to cut than porcelain and usually carry a PEI (Porcelain Enamel Institute) rating of 0 to 3 (see PEI ratings below). Ceramic tiles are suitable for light to moderate traffic and are more water-absorbent, making them less frost-resistant than porcelain. In addition, they're usually more prone to wear. However, with new technologies, ceramic tile should always be considered by its specifications, as durability and other factors will vary among ceramic tiles. Ceramic tiles generally cost less than porcelain tiles.