sedimentary

Travertine

Calcareous Tufa (CaCO3)

Hardness: 3 on Mohs scale; Color: Tan, brown, or cream; Luster: Dull to earthy; Crystal structure: Trigonal; Cleavage: Perfect rhombohedral (microscopic); Specific gravity: 2.71; Texture: Porous, vesicular, or pitted.

Hardness: 3 on Mohs scale
Color: Tan, brown, or cream
Luster: Dull to earthy

Identified March 30, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed by the rapid precipitation of calcium carbonate, often at the mouth of a hot spring or in a limestone cave. The porous nature is caused by the escape of carbon dioxide and the encrustation of organic matter/plants during the Holocene to Pleistocene periods.

Uses & applications

Used extensively as a building material for facades, wall cladding, and flooring. In industry, it is used for landscaping, garden stones, and sometimes as a flux in glass making.

Geological facts

The Roman Colosseum is the largest building in the world constructed mostly of travertine. Its name originates from the Italian word 'travertino,' which is a derivation of the Latin 'tiburtinus,' meaning 'of Tibur' (modern-day Tivoli).

Field identification & locations

Identify in the field by its sponge-like or 'swiss cheese' appearance and its vigorous reaction (effervescence) to cold dilute hydrochloric acid. It is commonly found in geothermal areas like Yellowstone or Tivoli, Italy. Collectors look for unique banding or fossilized plant impressions.