Polished stone has a shiny, mirror-like surface. Marble, granite, limestone and travertine tiles and slabs are polished on large polishing machines which progressively grind the stone from the rough saw-cut surface (visible on the back side of tiles or slabs) to a specular (mirror-like) finish. This is accomplished by finer and finer circular polishing heads moving over the surface of the slabs or tiles as they move along a polishing line, until the desired finish is achieved. This is a process analogous to finishing wood, in which finer and finer sandpaper is used to smooth the surface.
Honed stone has a matte or satin finish for a softer, more subdued look. This is achieved at the factory by stopping just short of the last stage of polishing. Some fabricators have special equipment and can hone marble in their shops by removing the factory polish. One feature of honed marble is that it doesn’t show etching as readily, or wear patterns on floors. It is preferred by some because it has a less formal, softer appearance than polished stone.
Flamed stone is produced by applying blowtorch-strength heat to the surface of granite, which actually pops some of the crystals and creates a deeply textured surface. Flamed granite is ideal for use outside and can also be used for dramatic effect as an accent material in a polished granite floor. In addition to its rough beauty, flamed granite has a highly textured surface, which gives it a very non-slip surface, ideal in an exterior installation where water might create a hazard, or where slip resistance is a concern.
Antiqued stone is (usually) marble tile that has been “tumbled” with sand, pebbles or steel bearings in order to create a weathered, aged finish. This rustic look is very popular for casual settings or as a contrast to polished stone, for example, on a backsplash in a kitchen. Because of the nature of the process, antiqued stone should definitely be sealed, as the surface is very vulnerable to staining and absorption of liquids.
Filled Travertine, formed by geysers, is full of holes created by gas bubbles trapped as the stone hardens. Unfilled travertine has been used as exterior cladding and dimensional stone since the days of ancient Rome, and can still be seen on the outsides of modern buildings. When travertine is used for tiles and slabs, it is usually “filled”—that is, the surface holes are filled with cement or sometimes epoxy, and then polished or honed like any other stone tiles or slabs. Sometimes, other stones which may have natural pits or fissures or voids will also be filled, usually with an epoxy compound colored to match the field color of the material. Additionally, one will sometimes see fiberglass matting epoxied to the back of some stones. This fill and/or backing is not an indication of inferior material, as some of the most beautiful and expensive stones can be quite vulnerable during the manufacturing and fabrication process.