Travertine is a form of limestone deposited by mineral spring, widely used in constructions, particularly in Rome, since the first Millennium BC.
The difference between the spongy calcareous type and the travertine layer is basically given by the geological formation of the soil: limestone is one of the most common deposits in nature, formed by a process of rapid precipitation of calcium carbonate dissolved in water.
A continental subaerial environment in which the limestone solution had time to stagnate and sediment in a flat area, close enough to the surface to be able to go through cycles of evaporation and re-flooding, little disturbed by water currents or springs, is ideal for the formation of the stone.
Its color depends on oxides incorporated (which happens quite easily, being by nature a fairly porous stone). Its natural color range from milky white to walnut, through a variety of shades from yellow to reddish. It frequently bears animal and plant fossils.
The industrial quality of its formation is related to its compactness. Generally, anyway, the travertine is a robust and malleable stone, which can be used for interior and exterior paving as well as sculptures.
Its aesthetic quality is appreciated by architects, given the variety of refined processing methods and industrial working obtained in the last fifty years.
In Italy, the best Travertine type comes from Guidonia and Tivoli in Lazio (from which the name “Roman travertine", called "lapis tiburtinus" by Latins), although there are also quarries in Tuscany (the Siena travertine), Umbria and Marche. The historical town of Ascoli Piceno is entirely built with this “warm” stone, which has been widely used for the construction of churches, buildings and squares since ancient times. One of the best-known examples is given by the famous colonnade of St. Peter’s square in Rome, designed and built by Gian Lorenzo Bernini in the eighteenth century, with stone from the Guidonia (Rome) quarries, still active today. Most of the material used by Bernini was found near the homonym Bernini quarry, where the upper layer was extracted for his work. Today you can still see the old Casal Bernini, the point from which the works were coordinated. The stone was extracted, processed and then transported to the Aniene River; from there it was shipped to Rome.
- Weight per unit of volume: 2450 - 2470 kg/m³
- Compression breaking load: 1110 - 1125 kg/cm²
- Flexural strength: 145 - 155 kg/cm²
- Abrasion resistance: 0,54 mm
- Moisture absorption (weight): 0,70 - 0,80 %
- Coefficient of thermal expansion: 0,0050 mm/m °C