sedimentary

Travertine (or Calcareous Tufa)

Calcium Carbonate (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 on Mohs scale; Color: White, cream, or tan; Luster: Dull to pearly; Crystal structure: Hexagonal/Trigonal; Cleavage: Perfect rhombohedral; Specific gravity: 2.71

Hardness: 3 on Mohs scale
Color: White, cream, or tan
Luster: Dull to pearly

Identified June 28, 2026More sedimentary →

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Physical properties

Hardness: 3 on Mohs scale; Color: White, cream, or tan; Luster: Dull to pearly; Crystal structure: Hexagonal/Trigonal; Cleavage: Perfect rhombohedral; Specific gravity: 2.71

Formation & geological history

Formed by the rapid precipitation of calcium carbonate, often at the mouth of a hot spring or in a limestone cave. Tufa is the porous variety formed in ambient-temperature water.

Uses & applications

Used extensively as a building material for flooring, wall cladding, and vanity tops. Smaller specimens are used in aquariums and landscaping.

Geological facts

The Colosseum in Rome is the largest building in the world constructed mostly of travertine. It is often confused with marble but is actually a sedimentary rock.

Field identification & locations

Identify by its porous, vesicular texture and its reaction (fizzing) when exposed to dilute hydrochloric acid. Commonly found in geothermal areas like Yellowstone or the Tivoli region of Italy.