Blend Tumbled French Pattern

Travertine-composed of calcium carbonate (CaCO3), and is technically a carbonate rock; travertine occurs in the vicinity of hot water sources and in caves. Groundwater containing calcium bicarbonate, rich in minerals, which is hot under hydrostatic pressure, loses pressure when it surfaces along a crack or reaches a cave-like cavity.

The CO2 that is dissolved in these waters is released into the atmosphere -- just like a bubbling soda when the lid is opened -- and solid calcite is deposited, resulting in travertine. Travertine can be thought of as a kind of marble, but it is separated from marble by its distinctive porous structure. These cavities in travertine are caused by gases that are trapped in it during its formation and then released.