Travertin
Characteristic
Calcareous tufa is characterized by a porous structure, porousness, low hardness (does not leave scratches on glass), light color (white, grayish, yellowish, brown), reaction to diluted hydrochloric acid. It is distinguished by its low density (from 1800 to 2500 kg/m³).
Calcareous tufa can be confused with limestone. The only visual difference is that calcareous tufa has a porous structure, while limestone has a dense structure.