 Traverton is a form of limestone deposited by mineral springs, especially hot springs. Traverton often has a fibrous or concentric appearance and exists in white, tan, cream-colored, and even rusty varieties. It is formed by a process of rapid precipitation of calcium carbonate, often at the mouth of a hot spring or in a limestone cave. In the latter, it can form stalactites, stalagmites, and other speleothems. It is frequently used in Italy and elsewhere as a building material. Traverton is a tristral sedimentary rock, formed by the precipitation of carbonate minerals from solution in ground and surface waters, and slash geothermal heated hot springs. Similar but softer and extremely porous deposits formed from ambient-temperature water are known as Tufa. Modern Traverton is formed from geothermally heated supersaturated alkaline waters, with raised PCO2C partial pressure. On emergence, waters do gas coat due to the lowered atmospheric PCO2, resulting in an increase in pH. Since carbonate solubility decreases with increased pH, precipitation is induced. Precipitation may be enhanced by factors leading to a reduction in PCO2. For example increased air-water interactions at waterfalls may be important, as may photosynthesis. Precipitation may also be enhanced by vibration in some springs. Both calcite and aragonite are found in hot spring Traverton's. Aragonite is preferentially precipitated when temperatures are hot, while calcite dominates when temperatures are cooler. When pure and fine, Traverton is white, but often it is brown to yellow due to impurities. Traverton may precipitate out directly onto rock and other inert materials as in chemical or magma hot springs for example.