Travertine is generally used for floors, walls, countertops and for outside as cladding and pavement. In its original form, travertine has many holes and voids that are generally filled with grout. It is then honed or polished, which produces a uniform surface more like other marbles. Unfilled travertine is also quite beautiful, and is often seen as exterior surfaces of buildings. Travertine stones result from hot spring water penetrating up through underground limestone. After water evaporates, it leaves layers of dissolved limestone and other minerals, giving it its banded appearance.