The use of the terms ceramic and porcelain can be confusing. The term “ceramic tile” is often used as a generic name for all types of tile (porcelain included). However, the term is also (and traditionally) used to describe a specific type of tile product that is made of white, red and/or brown clays mixed in with various minerals. This type of tile is often very porous and will typically be glazed with a glass like coating that both decorates the face of the tile as well as protects it from staining and scratching. Glazed ceramic floor tile is an extremely durable product suitable for all areas of the home *.
Porcelain tile is also comprised of clays and other minerals however; in addition, it has a large content of feldspar. Feldspar is a mineral that when heated (fired) in the kiln will improve the strength, toughness, durability and density of the ceramic body. A porcelain tile is defined by its density which is measured by water absorption rate. To be porcelain tile the water absorption rate needs to be .5% or less. To better illustrate this, if you place a drop of water on a porcelain tile only .5% of that drop will be absorbed into the tile. This density makes porcelain tile extremely stain resistant. Also because of this low absorption rate, some porcelain tile products are suitable for exterior applications.
Porcelain tile comes both glazed and unglazed. The glazing which is very durable is often for decorating purposes. Unglazed porcelain tile can be the most durable of all the ceramic tile categories and are often found being used in heavily trafficked areas such as airport terminals and other large public spaces.
Most factories today are producing porcelain tile products due to consumer demand.
* Note that there is a distinction of ceramic wall tile. This this type of clay tile is made of talc. Talc is a lightweight mineral and when used in ceramic tile it is only suitable for wall tile applications.