By Cory Sekine-Pettite
Ancient Romans made extensive use of travertine in constructing their historic structures. Photo courtesy of JupiterImages 2007
Travertine is a sedimentary rock that began as limestone (calcium carbonate), which over time was heated by the Earth's core, releasing pressurized water and steam to form hot springs. The rising hot water would dissolve the limestone and bring with it granules of stone from below the surface that collected into mud baths. When this mud cooled, it would crystallize into solid stone, now called travertine. The stone is often light in color and beautifully banded as a result of the presence of iron compounds or other organic impurities.
The rock derives its name from Tivoli, Italy, which in ancient Roman times was known as Tibur. The ancient name for the stone ? which was used extensively as a building material ? was lapis tiburtinus meaning tibur stone, which has evolved today to travertine.
The building stone is used most widely in the Mediterranean region (Italy, Greece and Turkey), but is common in the United States as well, particularly for paving patios and garden paths, showers, wall coverings and countertops, though it has been used in exterior applications on commercial and institutional structures as well, such as the Getty Center in Los Angeles.
Quarries of travertine
Quarried mostly in European countries, particularly around the Mediterranean Sea, travertine is a popular imported building stone in the United States, although there are domestic quarries in New Mexico as well. By the time the stone is removed from the earth, it reveals a smooth, often milky color and a dense building material that evokes a certain Old World charm.
Travertine is removed in large blocks and either cross cut or vein cut, yielding a beautiful stone with either method. Cross cutting is performed with the grain and on the same layer as it formed in the earth. Vein cutting goes across several layers of stone bedding, making for a more stippled or tiger-stripe effect when cut into tiles. The stone is available in a number of finishes, including polished, honed, tumbled and brushed.
Colors of travertine
Pure travertine is a creamy white color, but the building stone is more often found in various shades of brown, yellow and even red because of the inclusion of other minerals. Common varieties include light beiges, walnut, desert gold and cherry red. The lighter, neutral tones work well for commercial interior and exterior projects. The stone will give those spaces a quaint sophistication and provide architectural interest without commanding all of the attention. And for interior residential projects, the richer travertine colors can be used to the opposite effect, if desired, making kitchens, bathrooms, stairways and other areas into conversation pieces.
The Mammoth Springs in Yellowstone National Park are a great example of how travertine is formed as a result of pressurized steam passing through limestone.
Applications of Travertine
It should be noted that travertine is characterized by the multitude of holes and depressions found on the surface of the stone, which imparts a unique character and is a major selling point for many people. To untrained eyes, travertine's texture may appear to be from damage; however, the holes formed naturally from the steam and water that passed through the rock during its formation. A good sealer will prevent any damage to travertine tiles placed in potentially messy or high-traffic areas, such as office space flooring or foyers. However, the stone also can be purchased as "filled," with the holes packed with grout or resin. This would probably be the ideal choice for applications where staining could be an issue, such as kitchen countertops.
Regardless of the intended application, travertine imparts an ageless beauty while providing a largely neutral color range that can be incorporated into any design scheme. Further, by using travertine, one can continue a building tradition that has lasted for thousands of years and harkens back to an ancient civilization that, to this day, still is considered one of man's greatest artistic and intellectual periods.
Perhaps the most well-known symbol of that civilization ? Ancient Rome ? and the largest known building constructed with travertine is the Coliseum in Rome. Completed under Emperor Titus in 80 A.D., the amphitheatre was constructed using a combination of concrete for the foundations, travertine for the piers and arcades, tufa infill between piers for the walls of the lower two levels, and brick-faced concrete used for the upper levels and for most of the passageways beneath the arena floor.
The Coliseum remained in use for nearly 500 years, with the last recorded games being held there as late as the 6th century. Though the structure has been ravaged by stone robbers, earthquakes and time, much of it still stands today as a testament to architectural genius and the building materials used in its construction. The landmark remains a popular tourist attraction and is a national symbol for Italy.
(Article from Building Stone Magazine)