Quaternary thermogene and meteogene travertine occurs globally, both in Hungary and abroad. Size and thickness of the individual deposits are highly variable. They can be classified on the basis of water temperature, morphological setting, depositional environment, microfacies and fabric. All travertine is composed of pure low magnesian calcite and its stable isotopic composition (d13C, d18O) may change according to the facies. Sr and Ba are typical and some places enrichment of heavy metals, U, Th, and REE were also reported. Travertine is generally related to karst water springs; therefore, tectonically-controlled karstification, cave and soil formations are very common. It can be rich in fossils and its water depth varies from some centimeters to tens of meters. Chronology and timing of travertine can be solved by applying numerical, calibrated and correlative methods.