a light-colored, dense type of tufa, as dripstone or flowstone, deposited in caves or around limy springs, lakes, or streams
See travertine in American Heritage Dictionary 4
(trăvˈər-tēnˌ, -tĭn)
noun
A light-colored porous calcite, CaCO3, deposited from solution in ground or surface waters and forming, among other deposits, stalactites and stalagmites.
A compact calcium carbonate used as a facing material in construction.