Travertine, which is also called calcareous sinter, is a dense, porous, banded calcareous deposit. It is creamy or reddish in colour and is composed of precipitated calcite. It generally occurs on the surfaces of limestone caves. It forms when spring water saturated with calcium carbonate reaches the ground surface and releases the carbon dioxide due to the low pressure. The calcium carbonate then accumulates at the mouth of the spring to form travertine. Travertine is usually in the form of irregular stalactite and stalagmite blocks with crust-like layers. Its inner part always contains voids left by the plant’s decay. The engineering characteristics and genetic analysis of travertine are important to construction projects. (See Calcareous Sinter).