Travertine, a metamorphic rock formed in limestone caves or hot springs, is often recognizable by the naturally occurring pits and crevices throughout its body caused by carbon dioxide evasion. Though technically a type of limestone that has been impacted by additional heat and pressure from the earth, travertine is sometimes called tumbled marble. Marble is also a form of limestone.
The color of travertine, which falls into the warm neutral range, is influenced by the amount of iron and other organic impurities found within the earth’s crust where particular slabs are mined. On the lighter side, travertine showcases ivory and beige though it can be more golden or even dark brown.
The pits are part of travertine’s inherent beauty, but you may prefer a smoother finish, which does not welcome and trap dirt and crumbs. To eliminate these natural pits, manufacturers fill them. The filler varies by fabricator but is most often either epoxy, a dust and resin mix or colored cement.
Some homeowners or installers choose to fill in tumbled travertine tiles on the job site. If the tiles have not been sealed beforehand, many of the crevices can be filled with grout. However, if the grout is rinsed too soon, some of the fillings may be washed away. Grout filling is also more prone to chipping. A better alternative is to apply a clear epoxy. When pouring epoxy, keep the area as clean and dust-free as possible while the resin dries, or the settling particles will mar the finish.
Honing is part of the fabrication process after the travertine has left the quarry. To create a smooth, warm finish, the travertine goes through a process akin to sanding wood that removes any ridges or bumps in the stone’s surface and results in a matte or dull sheen. The grinding process begins with coarse polishing pads. As the surface becomes more level, finer polishing pads are used.
While the honing process will eliminate the more shallow, surface-level crevices, it would not automatically fill in every natural pit in the travertine. In most cases, a honed stone has been filled to eliminate any crevices or cracks, but not always.
Travertine’s natural state, with the pits and crevices, is considered a tumbled finish. Even a tumbled finish, however, will receive some minor sanding or polishing to remove rough edges and form the stone into tiles, pavers or other materials.
A chiseled finish, which applies more to the edge treatment of the stone, is similar to a “live” or “raw” edge. The look is similar to the multiple layers that can be found in slate tiles.
A polished finish takes the surface-finishing process beyond honing to buff the travertine to a glossy, mirror-like sheen.