Glazed ceramic tile is more popular. It's made by firing dried clay through a kiln twice, with a coat of glaze applied before the second firing. It's available in any color or design, and can be used to give your floor a dramatic look. It can also be made to mimic more expensive natural stone tile. The dense quality of the material makes it waterproof, and thus ideal for bathroom and kitchen floors, or even outdoor patios.
Unglazed ceramic tile is different from glazed in that it is only fired in the kiln once and it has no layer of glaze applied to the top. This means that although it is water resistant, it isn't waterproof like glazed ceramic tile. Unglazed tile is made from all natural ingredients, and gives a natural, earthy look to any room where it is installed.