The glaze is usually tinted and is a liquid glass layer that is baked into the surface and gives the tile its final color. If glaze is then polished, the tile must be sealed after installation to make it non-porous. The glaze finish makes the tile stain resistant and provides an infinite number of color and texture options. Glazed porcelain tiles are the most common variety chosen by homeowners because of durability and the large array of designs available. They can imitate the appearance of natural stones like granite, limestone and slate, as well as metals like aluminum and brass. Some varieties even look like hardwood. Glazed porcelain tiles are admired for their glossy beauty and durability and can be used on any surfaces.