Travertine Formation

Travertine is a sedimentary rock. It is a natural chemical precipitate of carbonate minerals; typically aragonite, but often recrystallized to, or primarily, calcite.

Travertine forms as calcium carbonate is deposited from the water of mineral springs or rivulets that are saturated with dissolved calcium bicarbonate. The spring water from which the calcium carbonate precipitates can be hot, warm or cold. The rate of deposition increases with the temperature of the water, or alternatively, when biotic material accelerates the process of precipitation.

The ornate columns of travertine in caves are an example of an inorganic chemical sedimentary rock.

Formation

When carbon dioxide-rich water percolates through rocks in limestone areas, the water dissolves the limestone (typical karst process) and becomes saturated. A drop in pressure and/or change in temperature causes the water to release the carbon dioxide as gas, much like carbonated beverages. The calcium carbonate then recrystallizes and small debris and living biotic material such as moss, algae, and cyanobacteria become encrusted. The biotic material may survive, and may continue growing on top.

Rich deposits of aged, dried and hardened travertine were mined by the Romans. The rock typically remains quite porous with numerous cavities. When pure and fine, travertine is white, but often it is brown to yellow due to impurities (other than carbonate minerals).
Travertine is still forming at Jupiter Terrace, Fountain Geyser Pool, Yellowstone National Park.

Occurrence

Extensive deposits exist at Tivoli, Italy, near Rome. Travertine derives its name from this town. Tivoli was known as Tibur in ancient Roman times. The ancient name for the stone was lapis tiburtinus, meaning tibur stone, which has been corrupted to travertine.

Detailed studies of the Tivoli travertine deposits revealed diurnal and annual rhythmic banding and laminae which have potential use in geochronology.

In Central Europe's last postglacial palaeoclimatic optimum (Atlantic Period, 8000-5000 B.C.), huge deposits of tufa formed from karst springs. Important geotopes are found at the Swabian Alb, mainly in valleys at the foremost northwest ridge of the cuesta, in many valleys of the eroded periphery of the karstic Franconian Jura, at the northern Alpine foothills, and the northern Karst Alps. On a smaller scale these karst processes are still working. Travertine was a very important building material for housing and representative buildings since the Middle Ages.

Travertine has formed sixteen huge, natural dams in a valley in Croatia known as Plitvice Lakes National Park. The travertine clings to moss and rocks in the water, and has built up over several millennia to form waterfalls up to 70 m in height.

Other beautiful cascades of natural lakes formed behind travertine dams can be seen in Band-i-Amir (Afghanistan), HuangLong Valley (Sichuan, China), Semuc Champey (Guatemala), and Pamukkale (Turkey). Many geyser fields also have colorful travertine deposits.

Travertine is often used as a building material. The largest building in the world constructed mostly of travertine is the Colosseum in Rome. Other notable buildings using travertine extensively include the Sacré-Cœur Basilica in Paris and the Getty Center in Los Angeles, California. The travertine used in the Getty Center construction was imported from Tivoli.

Travertine is one of several natural stones that are used for paving patios and garden paths. It is sometimes known as travertine limestone, sometimes as travertine marble; these are the same stone, even though it is neither limestone nor marble. The stone is characterised by pitted holes and troughs in its surface. Although these troughs occur naturally, they suggest to some eyes that considerable wear and tear has occurred over many years. Some installers use a grout to fill these holes, whereas others leave them open — travertine can even be purchased "filled" or "unfilled." It can be effectively polished to a smooth, shiny finish and comes in a variety of colors from grey to coral-red. Travertine is most commonly available in tile sizes for floor installations.

Travertine is one of the most frequently used stones in modern architecture, and is commonly seen as façade material, wall cladding, and flooring. Architect Welton Becket was one of the most frequent users of travertine, incorporating it extensively into many if not most of his projects. The entire first floor of the Becket-designed UCLA Medical Center has thick travertine walls.

There are two or three small travertine producers in the western United States. U.S. demand for travertine is about 0.85 million tons, almost all of it imported. Most of the imports come from Turkey, Mexico, Italy, and Peru. A decade ago, Italy had a near monopoly on the world travertine market.

Travertine Tile

Tile options are usually products of either cross-cut or vein-cut methods. Cross-cut follows the grain of the bedding and its layers to produce a consistent texture. Vein cutting goes through layers of stone bed and creates a more striated and freckled appearance.

Contemporary travertine comes in diverse finishes, the most popular being honed or polished. Honed tiles are polished for a smooth matte surface. Tumbled travertine is rolled with gravel to give it an uneven, unpolished, and rough rustic appearance. Filled travertine tiles are those whose pits and crevices are filled with resin or cement for a smooth, solid surface. Tile edges are even sharp to give it a standard shape and size.

On the other hand, unfilled travertine tiles give it a singularly unique and old-world look that harkens back to the antiquities age.

Filled tiles are much easier to clean than unfilled travertine tiles since dirt particles can fall in the crevices, pits and uneven surfaces. The polished travertine tiles are the popular choices for residences. A smooth, pristine surface reflects natural light and allows for a glossy touch to the tiles. Combined with the subtle variations in shades and vein markings, travertine is a versatile home construction material.

It is normally available in standard 12” x 12” or 18” x 18” cuts. Proper attention must be given to its maintenance. Travertine absorbs oils and is vulnerable to hard scratches and acids. If it will be used in the bathroom and kitchens, it must be treated with a sealer to protect it against staining.

	grout GROUT The material used to fill in the joints between stone tile. Grout can be cement or plastic resins.

	limestone LIMESTONE A sedimentary rock composed of calcium carbonate.

	Marble MARBLE: CHARACTERISTICS This standard includes general information on the characteristics and common uses of marble and identifies typical problems associated with the material. INTRODUCTION Marble is an extremely hard, metamorphic stone composed of calcite (CaCO3). It is formed as a result of the recrystallization of limestone under the intense pressure and heat of geologic processes. The effect of this process is the creation of a stone with a very tight crystalline structure and small but definite porosity. Because of its structure, marble can take a very high polish and is a very popular decorative stone for architectural and sculptural uses. The limited porosity of marble, especially polished marble, makes it less vulnerable to the leaching effects of water. Calcium carbonate, however, of which marble is composed, is highly susceptible to attack by acidic agents. Marble is readily dissolved by acids, even very dilute acids, however the actual results of acidic exposure will vary with the nature of the acid. Chlorides, nitrates, sulfates and other chemical compounds react differently with marble and produce various by-products, which have a wide range of solubility and impact on the durability of marble. For this reason, it is always important to determine the exact type of pollutants causing marble deterioration. Marble itself can be of two types, one composed of calcite and the other of dolomite. Dolomitic marble is much more resistant to acid attack than calcite marble. The color of marble ranges from the brilliant white of calcite to black, including blue-gray, red, yellow and green, depending upon the mineral composition. TYPICAL USES Marble has many decorative and structural uses. It is used for outdoor sculpture as well as for sculpture bases; in architecture it is used in exterior walls and veneers, flooring, decorative features, stairways and walkways. The way in which the stone is used may be a factor in limiting or controlling the severity of exposure. The use or function of the marble may also affect the feasibility of applying certain treatments, but type of use is not the primary factor in the major types of deterioration and damage to which marble is susceptible.