Travertine (from Italian word “travertino”, what means tibur stone) – tufa, polycrystalline fragile grained homogeneous rock, formed by calcium carbonate’s minerals (mainly formed by aragonite with small share of calcite), limescale from carbonated spring. Travertine can be grinded or polished. In the first century BC, travertine was known as lapis tiburtinus (the stone from Tibur).
Travertine forms in consequence of calcium carbonate’s sedimentation from carbonated spring’s water. Also it can form from groundwater in caves, in this way it becomes stalactites and stalagmites. Travertine forms in consequence of chemical reaction: Ca(HCO3)2 \toCaCO3+H2O+CO2. In the result of this reaction insoluble calcium carbonate emits. Travertine can be used as freestone or facing stone (and also can be used for facing inside premises). Besides it can be used in agriculture for soil liming.
The biggest building which was made with using travertine is Colosseum. In time when it was building, builders used striped light yellow roman travertine from Sabine mountains. Travertine also was used during the construction of the Cathedral of St. Peter in the Vatican.
In Russia St. Petersburg metro station “Vyborgskaya”, the central mosque in Grozny, and many another religion places of Chechen Republic were made with using travertine. Because of instability to the effects of gas (smoke, fuel, exhaust), travertine is more useful as decorative material. It can be used as tile for flooring.
Nowadays artificial imitation of travertine is also popular. Artificial travertine has the same color and porosity, but another composition. It is made from colored cement, this is why artificial travertine is more strong to weatherproof.