Iranian travertine
Travertine is a limestone formed by precipitation of lime from water supersaturated with calcium carbonate (lime) from hot springs. Mohs hardness 3 to 4 BICK processing group 3. Travertine always has more or less small and sometimes larger holes. Weather resistant.
Travertine is formed when the CO2 content in the water decreases (e.g. due to a rise in temperature) and lime deposits occur. This can be expressed with the following chemical equation: