Ceramic tiles are thin slabs of clay or other minerals tightly compressed and heated in an oven to create a hard and durable building material. Ceramic tiles can be glazed or unglazed, and can come in many different colors, shapes and sizes. There are many different types of ceramic tiles, each manufactured in different ways with different material components for a wide array of applications. Ceramic tiles can be made to suit exterior and interior applications. There are ceramic tiles made for use on walls, floors, counter tops and more. Porcelain tiles are among the most popular and durable types of ceramic tiles. Porcelain tiles are ceramic tiles that have heated at a greater temperature than typical ceramic tiles, making them more durable and less porous and therefore less water absorbent. A porcelain tile must have a water absorption rate of less than 0.5% to be classified as porcelain. All porcelain tiles are ceramic, but not all ceramic tiles are porcelain. Glass tiles are not considered ceramic tiles but are another popular type of tile often used on walls, backsplashes and in other accent applications. Natural stone tiles (tiles produced from cuts of naturally occurring stone such as granite or travertine) are also an alternative to ceramic tiles and can be used in a number of applications.