Travertine

Travertine is a limestone that forms from chemical precipitation of calcium carbonate found (as CaHCO2) in supersaturated alkaline waters originated in the Appenines mountains. Since carbonate solubility decreases as temperature and pressure decrease or PH increases (water Co2 degassation) or pCO2 (photosynthesis), precipitation of carbonate from these waters is induced. The originated mineral deposit is characterized by a porous structure and the presence of numerous voids due to plants that deposited along with the mineralization in the sedimentary basin.