Travertine is a sedimentary rock formed from terrestrial limestone deposited around mineral springs, especially hot springs. It often has a fibrous or concentric appearance and exists in white, tan, cream 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. Similar (but softer and extremely porous) deposits formed from ambient-temperature water are known as tufa.
Travertine is sometimes also defined by its mode of origin, as rock formed by inorganic precipitation of calcium carbonate minerals onto a surface following exchange of carbon dioxide between the atmosphere and groundwater.
ENJOY - The Zuni Fetishes carved from travertine!